History
How we know the past

What Is History?

History is not the past itself, which is gone, but the story we build from what the past left behind. The word comes from the Greek historia, meaning inquiry, and that is still the job: asking questions of evidence and following the answers wherever they lead.

The written record begins around 3200 BC, when scribes in Mesopotamian cities such as Uruk started pressing signs into clay. Everything before is usually called prehistory, known through bones, tools and buildings rather than words. The first people to call themselves inquirers into the past came much later. Around 430 BC Herodotus of Halicarnassus set out to explain why Greeks and Persians had gone to war, travelling widely, interviewing priests and weighing rival stories. His successor Thucydides, writing about the war between Athens and Sparta, was sterner: he distrusted legend and tried to check his witnesses against one another.

Other traditions reached the same idea independently. In China, Sima Qian completed his Records of the Grand Historian around 90 BC: 130 chapters spanning some two thousand years, from legendary sage kings to his own emperor, Wu of Han. He used court archives, visited sites himself, and his mix of annals, tables and biographies shaped official Chinese history for two millennia. In 1377 the North African scholar Ibn Khaldun wrote the Muqaddimah, an introduction to history that asked why dynasties rise and fall and warned readers against reports that defy common sense.

The modern discipline took shape in nineteenth-century German universities. Leopold von Ranke urged historians to show the past "as it actually was", insisting on original documents studied in archives. In 1961 the British historian E. H. Carr gave a series of lectures called What Is History? and answered his own question with a famous phrase: "an unending dialogue between the present and the past". Facts, he argued, do not speak for themselves; the historian decides which ones matter.

Did you know? The Roman orator Cicero was the first to call Herodotus the "father of history"; later critics, doubting some of his tales, nicknamed him the father of lies.

So history is both evidence and argument. It draws on documents, objects, landscapes, DNA and memories, and every generation brings new questions about women, climate, trade or disease. That is why history keeps being rewritten while the past stays exactly where it was. Knowing how the story is made is also the best defence against those who would tell it falsely. The past cannot be changed, but it can always be better understood.

Primary and Secondary Sources

Every piece of history rests on sources, and historians sort them into two families. A primary source was made at the time by someone close to the events: a letter, a tax register, a photograph, a coin, a diary. A secondary source is made later by someone studying the primary ones: a biography, a textbook, a documentary, or indeed this book.

Some of the oldest primary sources are bureaucratic. The Amarna letters, around 380 clay tablets found in Egypt in 1887, are diplomatic correspondence from the 14th century BC, written mostly in Akkadian cuneiform between the pharaoh's court and the rulers of Babylon, Mitanni and Canaan. At Vindolanda, a Roman fort near Hadrian's Wall, archaeologists have recovered hundreds of thin wooden writing tablets since 1973, most from around AD 100: duty rosters, a request for more beer, a parcel of socks and a birthday invitation from Claudia Severa to her friend Sulpicia Lepidina. In 1086 William the Conqueror's officials surveyed England for the Domesday Book, recording who held land and what it was worth.

Diaries bring a more personal voice. Samuel Pepys kept his in shorthand from 1660 to 1669, and his account of the Great Fire of London is still the eyewitness version historians quote most.

Did you know? As the Great Fire spread in September 1666, Pepys dug a pit in his garden and buried his wine and his Parmesan cheese to save them from the flames.

Primary does not mean true. Every source was made by someone, for someone, for a reason. The Domesday Book shows what the king wanted to tax, not how peasants felt; a general's dispatch flatters the general. So historians practise source criticism: they ask who made a document, when, for whom and why, what it leaves out, and whether other evidence agrees. Two modest sources that independently match can outweigh one confident one.

The line between the families also moves with the question. Edward Gibbon's The History of the Decline and Fall of the Roman Empire, published between 1776 and 1789, is a secondary source on Rome but a primary source on how an Enlightenment gentleman thought. A Victorian textbook is useless on the Tudors and priceless on Victorian schooling. Encyclopaedias, which summarise secondary work, are sometimes called tertiary sources: good maps, poor ground.

The habit of tracing a claim back to where it came from has never mattered more. A screenshot, a quotation on a poster or a viral clip is only as good as its origin, and asking the historian's questions of it is the simplest defence against being fooled.

Archaeology: Reading the Ground

Archaeology is the study of the human past through the things people left in the ground: tools, rubbish, bones, walls, seeds and even the dark stains where wooden posts once stood. It reaches far back beyond writing, and even for literate societies it records lives no scribe bothered to mention.

The urge to dig is old. Nabonidus, the last king of Babylon in the 6th century BC, excavated the foundations of ancient temples to find the names of the kings who built them. In the 1920s Leonard Woolley, digging at Ur, found a room of older objects with labelled clay cylinders, which some describe as a museum kept by Nabonidus's daughter, Ennigaldi-Nanna. In 1784 Thomas Jefferson cut a trench through a burial mound in Virginia and noted its layers, a step often called the first scientific excavation. Treasure hunting still dominated for a long time: the early diggers at Pompeii, from 1748, tunnelled for statues and largely ignored ordinary houses.

The key insight of modern archaeology is context. An object's position, the soil around it and what lies beside it say more than the object alone. Because digging destroys the evidence it uncovers, every layer must be recorded as it goes, with plans, section drawings, photographs and numbered context sheets. In the 1930s Mortimer Wheeler laid out excavations as a grid of square boxes divided by standing walls of earth, called baulks, so that the layers could be read in their sides.

Archaeology also corrects prejudice. Colonial writers insisted that the great stone enclosures of Great Zimbabwe, built between about the 11th and 15th centuries, could not be African work. In 1929 Gertrude Caton-Thompson's excavations showed that they were built by the ancestors of the local Shona people. In 1974 farmers digging a well near Xi'an in China broke into the Terracotta Army, thousands of clay soldiers guarding the tomb of the First Emperor.

Did you know? When the Sutton Hoo ship burial was excavated in 1939, its timbers had rotted away completely; archaeologists traced the 27-metre ship from rows of iron rivets left in the sand.

Today much archaeology happens without a spade. Aerial photography, ground-penetrating radar and lidar, laser scanning from aircraft, can see through forest canopies: surveys since 2018 have revealed tens of thousands of Maya structures under the Guatemalan jungle. Excavation itself is increasingly reserved for sites threatened by building. Each trench is an experiment that can never be repeated, so the real product of a dig is not the finds but the record.

Stratigraphy: Layers of Time

Stratigraphy is the study of layers, or strata, and it rests on a rule simple enough for a child: in an undisturbed pile, what is at the bottom was laid down first. Rubbish, floors, fallen walls, flood silt and ash build up over time, so a section cut through the ground is a calendar read from the bottom up.

The rule was set out in 1669 by the Danish scientist Nicolas Steno, studying the rocks of Tuscany, and is known as the law of superposition. Geologists such as William Smith, whose 1815 map of England and Wales was the first geological map of a whole country, used it to order the history of the Earth. Archaeologists borrowed it in the 19th century, and it remains the backbone of every excavation.

Nowhere shows it better than a tell, the Arabic word for a mound made of settlement upon settlement. At Hisarlik in north-west Turkey, the site of Troy, archaeologists distinguish nine main cities stacked over some three thousand years. Heinrich Schliemann drove a huge trench into the mound from 1871, looking for Homer's city, and destroyed much of the evidence he sought. The hoard of gold he found in 1873 and called Priam's Treasure came from a layer more than a thousand years older than any likely Trojan War. At Jericho, Kathleen Kenyon's careful trenches in the 1950s reached a stone tower built around 8000 BC, one of the oldest monumental structures known.

Did you know? Schliemann smuggled Priam's Treasure out of the Ottoman Empire; it vanished from Berlin in 1945, and only in 1993 did Russia admit that it lay in Moscow's Pushkin Museum.

Real ground is rarely so tidy. People dig pits, wells and graves that cut down through older layers, and burrowing animals shuffle small objects up and down. Archaeologists therefore record each deposit and each cut as a separate numbered context and work out which came before which. In 1973 Edward Harris, working on excavations in Winchester, devised the Harris matrix, a diagram that shows these relationships for thousands of contexts at once.

Layers give relative dates: older or younger. Objects inside them can add absolute ones. A coin minted in AD 330 sealed within a burnt layer proves the layer formed in or after 330, a limit archaeologists call the terminus post quem, the date after which. Combined with radiocarbon and tree rings, the humble layer cake becomes a precise clock. Read carefully, the ground keeps its own diary.

Radiocarbon Dating

Radiocarbon dating measures how long ago a living thing died. It works on anything that once took in carbon from the air or from food: wood, charcoal, bone, seeds, shell, cloth, parchment. Since its invention it has done more than any other technique to put dates on the human past.

The method rests on a quirk of physics. High in the atmosphere, cosmic rays turn a little nitrogen into carbon-14, a radioactive form of carbon. It mixes into the air as carbon dioxide, plants absorb it through photosynthesis, and animals and people absorb it by eating plants. While an organism lives, its share of carbon-14 matches the air. When it dies, intake stops and the carbon-14 decays at a steady rate, halving roughly every 5,730 years. Measure what is left and you can work out the time since death, back to about 50,000 years.

The American chemist Willard Libby and his team at the University of Chicago developed the method in the late 1940s, testing it on objects of known age such as wood from Egyptian tombs. Libby received the Nobel Prize in Chemistry in 1960. Results are reported in years "before present", with the present fixed at 1950 so that dates do not drift as time passes.

Did you know? Nuclear bomb tests in the 1950s and early 1960s nearly doubled the carbon-14 in the northern atmosphere, and scientists now use this "bomb pulse" to date modern wine, ivory and even human cells.

Then came a surprise. The amount of carbon-14 in the air has not been constant, so raw dates can be out by centuries. Researchers corrected them with wood of known age, counting back through the rings of long-lived bristlecone pines and European oaks; today's international calibration curve is called IntCal. The effects were dramatic. In 1973 Colin Renfrew's Before Civilization showed that the megalithic tombs of Atlantic Europe were older than the pyramids of Egypt, demolishing the old idea that every invention had spread outwards from the Near East.

A second revolution came with accelerator mass spectrometry, which counts carbon-14 atoms directly and needs only a few milligrams. In 1988 laboratories in Oxford, Zurich and Arizona each dated small samples of the Shroud of Turin and placed the linen between about 1260 and 1390. The same precision has dated the Ice Age paintings of Chauvet Cave in France to more than 30,000 years ago, and the first farmed crops of China and Mexico. Every living thing, it turns out, carries a clock that starts the moment it dies.

Tree Rings and Ice Cores

Two of the most precise calendars in history were not made by people at all. Trees add a new ring every growing season, and the polar ice sheets add a new layer of snow every year. Read correctly, both give dates to the exact year and record what the weather was doing.

Dendrochronology, tree-ring dating, was developed by the American astronomer Andrew Ellicott Douglass, who was looking for links between sunspots and climate. Wide rings mark good growing years and narrow ones drought or cold, so trees in the same region share a pattern of thick and thin, like a barcode. By matching overlapping patterns from living trees, old beams and buried timbers, researchers build continuous master chronologies. In 1929 a charred beam from Show Low, Arizona, closed the last gap in Douglass's sequence and dated the great Ancestral Puebloan buildings, such as Pueblo Bonito, for the first time.

European oak and pine chronologies now stretch back more than 12,000 years. They show that the oak for the Oseberg ship, a Viking burial in Norway, was felled in AD 834. In 2021 researchers found the trace of a cosmic-ray burst of AD 993 in wood cut by the Norse at L'Anse aux Meadows in Newfoundland, then counted the rings beyond it to show the trees were felled in 1021. That is the earliest firm date for Europeans in the Americas.

Ice cores work on a far larger scale. Drills in Greenland and Antarctica bring up cylinders of ice in which each year's snowfall forms a visible band near the top. Tiny air bubbles sealed in the ice preserve samples of ancient atmosphere, so scientists can measure past carbon dioxide directly. The European EPICA core from Dome C in Antarctica reaches back about 800,000 years.

Did you know? Greenland's ice records lead pollution from Roman silver mining and smelting, rising and falling with the fortunes of the Roman economy, more than 1,500 years before the Industrial Revolution.

Both archives record catastrophe. Volcanic eruptions leave layers of ash and sulphate in the ice and cold, stunted rings in trees. Together they show that eruptions in AD 536 and around 540 brought years of cold summers across the Northern Hemisphere, matching chronicles that describe a dim sun and failed harvests. The Icelandic Laki eruption of 1783 left the same double signature. Historians now set accounts of famine beside these natural records to test what people wrote. The trees and the ice were taking notes all along.

Archives and Record Offices

An archive is a collection of records kept because they might be needed again: by the body that made them, by lawyers and, eventually, by historians. Unlike a library, which gathers published books, an archive holds unique documents, and their meaning depends on keeping them in the order and groups in which they were created.

Archives are as old as writing. At Ebla in northern Syria, Italian archaeologists in 1974 and 1975 found thousands of clay tablets from the 24th century BC lying where they had fallen from wooden shelves when the palace burned. The fire that destroyed the city baked the tablets hard and preserved them. Temples and palaces across Mesopotamia kept similar stores of contracts, accounts and letters, and in imperial China the archives of each dynasty became the raw material for the official history written by its successor.

The modern public archive is a child of the 18th and 19th centuries. Spain gathered the papers of its American empire into the Archivo General de Indias in Seville in 1785. After the French Revolution the Archives nationales in Paris became the property of the nation, and French archivists formulated the principle of provenance: keep each body's records together and never re-sort them by subject. In Britain the Public Record Office Act of 1838 brought scattered legal records under one roof. Its successor, The National Archives at Kew, still holds Domesday Book.

Did you know? The Vatican's famous "Secret Archive" was never secret in the modern sense; secretum meant private, the pope's own papers, and in 2019 it was renamed the Vatican Apostolic Archive.

A record office works like a filter. Most of what any organisation produces is destroyed; archivists appraise records and keep only those of lasting value. What survives is boxed in cool, dark strongrooms, catalogued from the whole collection down to the single item, and produced for readers who must use pencils, not pens. Losses can be terrible: the Public Record Office of Ireland was destroyed by explosion and fire in 1922, at the start of the Civil War, taking centuries of records with it.

Archivists can also be heroes. In 2012 and 2013, while armed groups occupied Timbuktu in Mali, librarians and families smuggled hundreds of thousands of manuscripts south to Bamako in trunks, by road and by river. Today the challenge is digital, because emails and databases can vanish when the software that reads them dies. An archive is a society's long-term memory, and like any memory it survives only if someone takes care of it.

Oral History and Memory

Oral history is the past as people tell it. For most of human existence it was the only kind there was, and in many societies it remains a living craft. It covers both tradition, stories handed down through generations, and testimony, the memories of people who lived through events, recorded by an interviewer.

In West Africa, hereditary bards called griots, or jeli in the Mande languages, have long served as walking archives, reciting genealogies and epics to music. The best known is the epic of Sundiata Keita, founder of the Mali Empire in the 13th century, which griots carried across the centuries before the historian Djibril Tamsir Niane published a prose version from one griot's telling in 1960. In the 1930s the American scholars Milman Parry and Albert Lord recorded singers in Yugoslavia who could perform epics thousands of lines long by building them from stock phrases. Their work convinced most scholars that the Iliad and the Odyssey grew out of the same kind of oral composition.

Oral tradition can carry facts for a remarkably long time. Peoples of the Pacific Northwest coast told of a winter night when the ground shook and the sea swept villages away. Geologists later found drowned "ghost forests" of dead cedars along the coast, and tree rings showed the trees had died between the growing seasons of 1699 and 1700. Across the ocean, Japanese village records describe an "orphan tsunami" that arrived with no earthquake felt in Japan.

Did you know? Matching the Japanese records with the evidence in America allowed scientists to date the great Cascadia earthquake to the evening of 26 January 1700, at around 9 pm local time.

Modern oral history took shape in the 20th century. Between 1936 and 1938 the Federal Writers' Project in the United States interviewed more than 2,300 formerly enslaved people, an irreplaceable record of slavery told by those who survived it. In 1948 Allan Nevins founded the first university oral history programme, at Columbia. Since then collections such as the Imperial War Museum's sound archive in London and the USC Shoah Foundation, which holds video testimony from Holocaust survivors, have gathered tens of thousands of voices.

Memory is not a recording, though. People compress events, borrow details from films and from one another, and reshape stories to fit what came later. Oral historians therefore check testimony against documents, but they also treat the distortions as evidence: what people misremember shows what an event came to mean. A good interview captures not only what happened but what it felt like. The voice of one witness can do what no tax register ever will.

Forgeries, Hoaxes and Myths

The past attracts fakers because it confers authority. A document can win land, an ancient bone can win fame, and a good story can flatter a nation. Exposing forgeries is one of the historian's oldest skills, and the tools range from grammar to chemistry.

The most consequential forgery in European history is the Donation of Constantine, a document in which the Roman emperor Constantine, who died in 337, supposedly handed the pope authority over Rome and the western empire. Probably written in the 8th century, it was cited for centuries in support of papal power. In 1440 the Italian scholar Lorenzo Valla showed that its Latin was full of words and titles that did not exist in Constantine's time. It was an early triumph of philology, the study of how language changes.

Science joined in later. In 1912 the amateur collector Charles Dawson announced Piltdown Man, a skull from Sussex that seemed to combine a human braincase with an ape-like jaw: a missing link, and an English one. In 1953 fluorine tests and close study revealed a medieval human skull and an orangutan jaw with filed-down teeth, stained to look ancient. In 1983 the German magazine Stern published extracts from the Hitler Diaries; within two weeks forensic tests showed that their paper contained a whitening agent not made until after the war. Their author, Konrad Kujau, was a dealer in fake militaria. In 2021 Yale University announced that its Vinland Map, presented in 1965 as a medieval map of North America, was a fake: the ink contained titanium dioxide, a pigment used only from the 1920s.

Myths are subtler, because nobody needs to forge anything. Medieval scholars did not think the Earth was flat; the notion was popularised in the 19th century, notably by Washington Irving's 1828 life of Columbus. Napoleon was about average height for a Frenchman of his day, and the legend owes much to confusion between French and English inches and to British cartoons.

Did you know? No Viking helmet with horns has ever been found; the horns largely come from costumes designed for the first complete staging of Wagner's Ring cycle in 1876.

Checking a source still begins with the same questions. Do its language, materials and content fit its supposed date? Can its history be traced from owner to owner? A gap in that chain of ownership, its provenance, is often the first warning sign. Today the same scepticism is needed for doctored photographs and synthetic video. A forgery always tells the truth about one thing: the moment and the motive of its maker.

Who Writes History?

Every history has an author, and every author stands somewhere. Who gets to write the story of the past, from whose records and for whom, shapes what later generations believe happened. The saying that history is written by the victors captures a real danger, even if it is far too simple.

For most of recorded time, history was written by and for the powerful. Egyptian temple walls show Ramesses II triumphant at the Battle of Kadesh around 1274 BC, although the battle most likely ended in stalemate. The Bayeux Tapestry, probably made in England in the 1070s for William the Conqueror's half-brother Bishop Odo, tells the Norman version of 1066, in which Harold is an oath-breaker. Court historians in China, Persia and Europe wrote dynastic histories that justified the ruling house.

Yet the defeated also left accounts. After the Spanish conquest of Mexico, Hernán Cortés sent self-serving letters to the Emperor Charles V between 1519 and 1526, and the veteran Bernal Díaz del Castillo wrote his own True History to correct the official story. Meanwhile the friar Bernardino de Sahagún worked with Nahua scholars and elders to compile what is now called the Florentine Codex, completed around 1577 in Nahuatl and Spanish, whose twelfth book tells the conquest as the Mexica remembered it. In 1959 the Mexican historian Miguel León-Portilla gathered such accounts in Visión de los vencidos, the vision of the vanquished.

Did you know? The line "history is written by the victors" is often credited to Winston Churchill, but no one has found it in anything he said or wrote.

The 20th century widened the cast. The French Annales school, founded by Marc Bloch and Lucien Febvre in 1929, turned attention from kings to climate, prices and daily life. In 1963 E. P. Thompson set out to rescue weavers and labourers from what he called "the enormous condescension of posterity". Women's history, Black history, the Subaltern Studies historians of South Asia from the 1980s and Indigenous scholars have recovered voices the archives had muffled, often by reading old documents against the grain of their authors.

Bias cannot be removed entirely, but it can be named. Historians cite their sources so that others can check them, and argue in public, which is how history corrects itself. Today anyone with a phone can record events and post them, while some governments still rewrite school textbooks to suit their aims. The question to ask of any account remains the same: who is speaking, and who has been left out?

Before Writing: Tallies and Tokens

Long before anyone wrote a sentence, people needed to remember quantities: how many days since the last full moon, how many sheep went out to pasture, who owed whom a jar of oil. The oldest answers are tallies, marks cut one by one into bone, wood or stone. They record numbers without recording language, and they are among the earliest records of any kind.

The oldest candidate is the Lebombo bone, a baboon's leg bone from Border Cave in the Lebombo Mountains of southern Africa, marked with 29 notches and dated to more than 40,000 years ago. The Ishango bone, found in 1950 near Lake Edward in what is now the Democratic Republic of the Congo, is roughly 20,000 years old and carries columns of grouped notches. Some researchers read a lunar calendar or simple arithmetic in its patterns; others see only a well-used tool. Historians debate how much meaning to load onto a few scratches, which is exactly the problem with evidence that cannot speak for itself.

In the Near East, from around 8000 BC, farmers began using small clay tokens: cones, spheres, discs and cylinders, each shape standing for a measure of grain, an animal or a jar of oil. The archaeologist Denise Schmandt-Besserat catalogued thousands of them from sites in Iran, Iraq, Syria and Turkey and argued that they formed an accounting system used for several thousand years. Around 3500 BC, at cities such as Uruk and Susa, accountants sealed tokens inside hollow clay balls called bullae, often pressing them into the soft surface first so that the contents could be checked without breaking the seal. Once the marks on the outside said everything, the tokens inside were redundant, and the flat impressed tablet followed. Her theory remains influential, though scholars still argue over the details.

Records without words appeared far beyond Mesopotamia. In the Andes, Inca officials kept the khipu, bundles of knotted cotton or camelid-fibre cords. In 1912 the scholar Leland Locke showed that many khipus use a base-ten place system, with knots higher on a cord counting for more. Specialist keepers recorded censuses, tribute and storehouse stocks across an empire of millions; whether some cords also stored names or stories remains an open question.

In England, the Exchequer accounted for taxes with split tally sticks. Notches showed the sum, the stick was split lengthways, and payer and Treasury each kept a half that matched only its twin. The system ran from the twelfth century until 1826.

Did you know? When officials burned the Exchequer's obsolete tally sticks in a furnace beneath the House of Lords in October 1834, the fire spread and destroyed most of the old Palace of Westminster.

A barcode, a bank ledger or a stamped loyalty card does the same job as a notched bone: it keeps a number outside someone's memory. Writing grew out of counting, and it never entirely stopped.

Cuneiform and the First Scribes

Cuneiform is the oldest known writing system, and it was made by pressing a cut reed into wet clay. The name comes from the Latin cuneus, "wedge", after the triangular marks the reed left behind. For some three thousand years, from Sumer to Persia, it carried laws, letters, prayers, recipes and an enormous quantity of receipts.

The earliest tablets come from Uruk, in southern Iraq, around 3300 BC. German excavators found thousands in the temple precinct of Eanna, and almost all of them are accounts: rations of barley, numbers of workers, heads of livestock. These proto-cuneiform signs began as pictures drawn in clay, a jar or an ear of grain, alongside number signs that echo the older clay tokens. Over the following centuries the pictures turned on their side, lost their curves and became clusters of wedges that a scribe could press quickly. Signs also acquired sound values, so a symbol could spell part of a word or a foreign name, and full sentences could be written in Sumerian and later in Akkadian.

Writing needed scribes, and scribes needed school. In the edubba, the "tablet house", pupils spent years copying sign lists, model contracts and proverbs, and surviving exercise tablets preserve their mistakes alongside their teachers' corrections. The first author known by name is Enheduanna, daughter of Sargon of Akkad, who served as high priestess of the moon god at Ur around 2300 BC and composed hymns that were copied for centuries.

Because clay hardens and fire bakes it, cuneiform survives where papyrus and parchment rot. Archaeologists have recovered hundreds of thousands of tablets, from school exercises and loan contracts to the Epic of Gilgamesh. In the fourteenth century BC, pharaohs and Near Eastern kings wrote to one another in Akkadian cuneiform, as the Amarna letters found in Egypt show, making it the diplomatic language of its day. The script was adapted for Hittite, Elamite, Urartian and Old Persian, and the latest securely dated tablet, an astronomical text from Babylonia, was written around AD 75.

Reading it again was a feat of nineteenth-century detective work. Henry Rawlinson risked his neck copying the trilingual Behistun Inscription carved for Darius I on an Iranian cliff. In 1857 the Royal Asiatic Society set a test: four scholars, Rawlinson, Edward Hincks, Henry Fox Talbot and Julius Oppert, translated the same newly found Assyrian text separately. Their versions broadly agreed, and the decipherment was accepted.

Did you know? In 1872 George Smith, a self-taught assistant at the British Museum, recognised on a tablet from Nineveh a flood story strikingly like Noah's, part of what we now call the Epic of Gilgamesh.

Every spreadsheet, contract and tax return is a distant descendant of those clay accounts. Writing was not invented to tell stories; it was invented to keep the books, and the stories moved in later.

Hieroglyphs and the Rosetta Stone

Egyptian hieroglyphs look like pictures, but they form a full writing system that mixes signs for sounds with signs for ideas. An owl usually stands for the sound m; a house plan can mean "house" or spell the sounds pr; and silent "determinatives" at the end of a word, such as a seated man or a pair of walking legs, tell the reader what kind of thing is meant. Written in rows or columns, the script could run either way, and the reader starts from the side the animals and people are facing.

The earliest examples come from tomb U-j at Abydos, where small bone and ivory labels made before 3100 BC already carry signs that appear to spell sounds. Whether Egypt borrowed the idea of writing from Mesopotamia or invented it independently is still debated. Alongside the formal hieroglyphs carved on temples, scribes wrote quickly in hieratic, a flowing ink script on papyrus, and from around 650 BC in demotic, an even faster hand for contracts and everyday business.

Knowledge of the script faded with the old temples. The last known hieroglyphic inscription was carved at the temple of Isis at Philae in AD 394. For fourteen centuries afterwards, European scholars treated hieroglyphs as mystical symbols rather than a way of writing a language, and their elaborate guesses were almost entirely wrong.

The key was a broken slab of granodiorite found in July 1799 by French soldiers working on a fort near Rashid, which Europeans called Rosetta, during Napoleon's invasion of Egypt. The Rosetta Stone carries one decree, issued at Memphis in 196 BC by a council of priests honouring the teenage king Ptolemy V, written three times: in hieroglyphic, in demotic and in ancient Greek. The British took the stone under the terms of the French surrender in 1801, and it has been in the British Museum since 1802. Popular myth makes it a dictionary; in fact it is a fairly routine text about temple honours and tax privileges.

Because the Greek could be read, scholars could compare. The English polymath Thomas Young showed that the oval rings called cartouches held royal names and that some signs were phonetic. Jean-François Champollion, who knew Coptic, the last stage of the Egyptian language, went further. Comparing the names Ptolemy and Cleopatra, the latter from an obelisk at Philae, he showed that hieroglyphs spelled the sounds of a real language, and he announced his results in his Lettre à M. Dacier in 1822.

Did you know? The hieroglyphic section of the Rosetta Stone is the most damaged part: only 14 lines survive, compared with 32 lines of demotic and 54 of Greek.

Today Egyptologists read tomb walls, tax records and love poems with confidence. The stone that unlocked them was carved to flatter a boy king, and it ended up giving a whole civilisation back its voice.

The Alphabet's Long Journey

An alphabet is a short set of signs, each standing roughly for a single sound, so that two or three dozen letters can spell any word in a language. Compared with the hundreds of signs a cuneiform or hieroglyphic scribe had to master, it was a radical simplification, and most of the world's alphabets descend from one invention made on Egypt's fringes.

The earliest evidence is a handful of short inscriptions from the turquoise mines of Serabit el-Khadim in Sinai, found by Flinders Petrie's expedition in 1905, and from Wadi el-Hol in Egypt, dated to roughly 1900 to 1700 BC. They seem to have been made by Semitic-speaking workers who borrowed Egyptian pictures and used each for the first sound of its name in their own language. An ox head, alp, stood for a glottal stop; a house, bayt, stood for b. This acrophonic trick is why the letter A, turned on its side, still shows an ox's horns.

By around 1050 BC the Phoenicians, merchants of the Levant coast, were writing with a fixed set of 22 letters, all consonants, and their ships carried it around the Mediterranean. The order of letters was already old: at Ugarit, in Syria, scribes of the fourteenth century BC pressed an alphabet of their own into clay with a cuneiform stylus, and their practice lists run in a sequence recognisably close to ours.

The Greeks adopted Phoenician letters around 800 BC and made a crucial change: they turned letters for sounds Greek did not use into vowels, so aleph became alpha. From Greek, by way of the Etruscans, came the Latin alphabet of Rome, now used for more languages than any other script. In the ninth century the missionaries Cyril and Methodius created Glagolitic to write Slavonic, and in the First Bulgarian Empire a new script based largely on Greek letters, later called Cyrillic in Cyril's honour, soon replaced it.

The eastern branch ran through Aramaic, the administrative language of the Persian Empire, which gave rise to the square Hebrew script and, through the Nabataean script of Petra, to Arabic. Whether the Brahmi script of India, ancestor of Devanagari and many others, also descends from Aramaic is still debated.

Did you know? Korea's Hangul is one of the few alphabets designed from scratch: King Sejong's scholars completed it in 1443, shaping some consonants after the mouth and tongue that pronounce them.

From Phoenician merchants to text messages, the alphabet has proved endlessly adaptable, gaining letters, losing them and changing shape on every new surface. A few dozen signs now carry the written words of most of the world's languages, and the ox still stands at the front of the line.

Paper, from China to the World

Paper is a thin mat of plant fibres, beaten to a pulp in water, caught on a screen and dried. The definition matters, because papyrus, parchment and bark cloth, which all came earlier, are not paper: papyrus is made from strips of reed pith laid crosswise, and parchment is animal skin. Paper was cheaper than both, could be made almost anywhere, and changed what people could afford to write down.

Chinese tradition credits a court official, Cai Lun, who in AD 105 presented the emperor with paper made from tree bark, hemp, old rags and fishing nets. Archaeology tells a longer story. Fragments of paper from the Western Han dynasty, two or three centuries older, have been found at sites such as Fangmatan in Gansu, one of them bearing a drawn map. Cai Lun probably improved and standardised a craft rather than inventing it, which did not stop him becoming the patron of papermakers.

The craft spread through East Asia, reaching Korea and then Japan by the seventh century, and west along the Silk Roads. A famous story says Chinese papermakers captured at the Battle of Talas in 751 taught the craft in Samarkand. Historians now think paper was already known in Central Asia, but Samarkand paper certainly became renowned. A paper mill was working in Baghdad by the 790s, and the cheap new material fed the city's booming book trade, its government offices and its scholars. By the tenth century paper was replacing papyrus in Egypt.

Europe learned from the Islamic world. Muslim Spain had paper mills by the twelfth century, notably at Xàtiva, near Valencia. Italian mills at Fabriano transformed the process from the late thirteenth century, with water-powered hammers, gelatine sizing that stopped ink from bleeding, and watermarks made by bending wire into the mould. Ulman Stromer opened one of Germany's first paper mills at Nuremberg in 1390, and England followed in the 1490s, just in time for printing, which would have been far less useful on costly parchment.

For centuries European paper was made from linen and cotton rags. Shortages of rags in the nineteenth century pushed inventors towards wood pulp, and continuous machines such as the Fourdrinier, patented in Britain in the early 1800s, turned out paper on endless rolls. Cheap newspapers, novels, school exercise books and forms in triplicate followed.

Did you know? Much nineteenth-century wood-pulp paper is acidic and turns brown and brittle, while many rag-paper books from the fifteenth century remain supple today.

Even in a digital age, paper is everywhere: in banknotes, packaging, passports and the parcel on the doorstep. Its journey from a Chinese workshop to every desk on Earth took well over a thousand years, and it arrived carrying a great deal of what we know about the past.

The Printing Press

Printing means making many identical copies by pressing an inked surface onto paper. Its history begins not in Germany but in East Asia, where Buddhists wanted to multiply sacred texts as acts of devotion, and carving a whole page into a block of wood was well established by the eighth century.

The oldest surviving printed book with a date is the Diamond Sutra, a scroll about five metres long printed in China in 868 and sealed in a cave at Dunhuang, where the explorer Aurel Stein acquired it in 1907; it is now in the British Library. Around the 1040s a commoner named Bi Sheng made movable type from baked clay, as the scholar Shen Kuo described in his Dream Pool Essays. Korean printers cast type in metal, and the Jikji, a Buddhist anthology printed at Heungdeok Temple in 1377, is the oldest surviving book printed with movable metal type. With thousands of Chinese characters to cast and sort, though, carved blocks often remained the practical choice.

Around 1450 in Mainz, the metalworker Johannes Gutenberg brought several technologies together. He devised a hand mould for casting letters quickly from an alloy of lead, tin and antimony, an oil-based ink that clung to metal, and a screw press adapted from those used for wine and paper. With only a few dozen letter shapes, the Latin alphabet suited the system perfectly. His 42-line Bible, finished around 1455, still astonishes with its crisp black columns; fewer than fifty copies survive. Gutenberg himself lost much of his equipment to his financier, Johann Fust, after a lawsuit in 1455.

The technology spread with startling speed. By 1500 presses were at work in hundreds of European towns. William Caxton set up England's first press at Westminster in 1476, and Venice became a capital of books. In 1517 Martin Luther's arguments against the sale of indulgences were reprinted across Germany within weeks, and the Reformation became the first great print campaign. The first press in the Americas began work in Mexico City in 1539.

Print standardised spelling, fixed texts so that scholars across a continent could cite the same page, and made scientific diagrams reproducible. It spread pamphlets, propaganda and forgeries just as efficiently.

Did you know? The Jikji, printed 78 years before Gutenberg's Bible was finished, is kept today not in Korea but in the Bibliothèque nationale de France in Paris.

Steam-powered presses, first used to print The Times in 1814, then rotary presses and offset lithography carried the revolution into the age of mass newspapers. Every web page and printed receipt owes a debt to those workshops in Dunhuang, Kaesong and Mainz. Copying stopped being a craft and became an industry.

Libraries, from Alexandria to the Archive

A library is a collection of texts gathered, ordered and kept so that someone else can find them later. That last part is what separates it from a pile: a library needs a catalogue, a building, a keeper and a reason to last longer than any single reader.

The oldest great library we can still handle belonged to Ashurbanipal, king of Assyria in the seventh century BC. Around 1850, Austen Henry Layard and Hormuzd Rassam excavated tens of thousands of clay tablets and fragments from his palaces at Nineveh, now in the British Museum. Ashurbanipal had texts collected and copied from across his empire: omens, medicine, word lists and the Epic of Gilgamesh. Notes on many tablets name the king as owner and call down curses on anyone who steals them.

The Library of Alexandria, founded under the Ptolemies in the early third century BC, aimed to own a copy of every Greek book. According to the physician Galen, books found on ships entering the harbour were seized and copied, and the owners sometimes received only the copy back. The poet Callimachus compiled the Pinakes, a catalogue of authors and works said to have filled 120 scrolls. Popular legend has the library destroyed in a single blaze, but historians describe a slow decline: a fire during Julius Caesar's war in 48 BC, purges of scholars, civil strife and dwindling funds over centuries. The tale that a caliph ordered its books burned first appears centuries after the Arab conquest and is widely treated as a myth.

Other traditions built just as boldly. In Baghdad, the House of Wisdom of the ninth century supported scholars translating Greek, Persian and Indian works into Arabic, until the Mongol sack of 1258. The Buddhist monastery of Nalanda in India drew students from across Asia for centuries before it was destroyed around 1200. In Timbuktu, family libraries kept manuscripts on law, astronomy and medicine, and in 2012 and 2013 librarians smuggled hundreds of thousands of them to safety in Bamako, away from occupying militants.

Modern libraries added a new promise: completeness by law. Thomas Bodley refounded Oxford's university library, opening it in 1602, and in 1610 he agreed with the Stationers' Company to receive a copy of every book its members registered, an early form of legal deposit. National libraries now collect books, newspapers and even websites, and the Internet Archive, founded in 1996, has saved hundreds of billions of web pages through its Wayback Machine.

Did you know? After British troops burned the young Library of Congress in 1814, Thomas Jefferson sold Congress his own library of 6,487 books to replace it.

Every library is a bet against forgetting. Some bets are lost to fire, flood or neglect, but enough are won that we can still read a king's omens from Nineveh.

Calendars and the Counting of Days

A calendar is a way of counting days so that people can plant crops, pay debts, hold festivals and agree on when something happened. The trouble is that nature's clocks do not fit together. A day is one turn of the Earth; a lunar month, from new moon to new moon, lasts about 29.5 days; and a solar year runs about 365.24 days. No whole number of days or months fits neatly into a year, and every calendar in history is a compromise between them.

The evidence is everywhere: monuments aligned to the Sun, almanacs, festival lists and inscriptions. Newgrange in Ireland, built around 3200 BC, admits the rising Sun into its inner chamber around the winter solstice. Egypt's civil calendar had twelve months of thirty days plus five extra days, a tidy 365 that slowly slipped against the seasons, while priests watched for the rising of the star Sirius that heralded the Nile flood. Babylonian astronomers kept a lunisolar calendar, adding a thirteenth month when needed, and found that 19 solar years almost exactly equal 235 lunar months, a cycle still used for the Jewish calendar and for calculating Easter.

Across the Atlantic, the Maya meshed a 260-day ritual count with a 365-day year, so that each combination recurred every 52 years, and kept a Long Count of days from a starting point in 3114 BC. The end of one great cycle on 21 December 2012 prompted predictions of doom, although Maya inscriptions refer to dates far beyond it. The Islamic calendar follows the Moon alone, with years of 354 or 355 days, so Ramadan moves through every season over about 33 years. The Chinese calendar is lunisolar, which is why Lunar New Year falls between late January and mid-February.

In Europe, Julius Caesar introduced the Julian calendar in 45 BC, with a leap day every fourth year. Its year of 365.25 days was about eleven minutes too long, and by the sixteenth century the spring equinox had drifted ten days. In 1582 Pope Gregory XIII decreed that Thursday 4 October would be followed by Friday 15 October, and that century years would be leap years only if divisible by 400. Catholic countries switched at once; Britain and its colonies waited until 1752, skipping eleven days in September, and Russia until 1918, which is why the October Revolution is commemorated in November.

Did you know? The story of mobs in 1752 shouting "Give us our eleven days" is largely a myth, apparently inspired by a placard in a satirical painting by William Hogarth.

Today atomic clocks keep time more steadily than the spinning Earth, and leap seconds have occasionally been added to keep the two in step; in 2022 the world's metrologists voted to stop adding them by 2035. The calendar on your phone is a Roman reform, patched by a pope and synchronised by satellites, still quietly arguing with the sky.

Maps and the Shape of the World

A map is an argument about space. It chooses what to show, what to leave out and what to put in the middle. People have drawn maps for as long as they have needed to find water, claim land or explain the world, and almost every map tells you as much about its makers as about the ground.

Naming the oldest map is hard, because it depends on interpretation. A wall painting at Çatalhöyük in Turkey, made around 6600 BC, has been read as a town plan beneath an erupting volcano, though some scholars see only a leopard-skin pattern. On firmer ground is the Babylonian Map of the World, a small clay tablet of around the sixth century BC now in the British Museum. It shows Babylon on the Euphrates, enclosed by a circular "Bitter River" of ocean, with mysterious regions beyond.

Around AD 150 in Alexandria, Claudius Ptolemy wrote his Geography, listing thousands of places by latitude and longitude and explaining how to project a curved Earth onto a flat surface. Chinese mapmakers developed their own grid: the Yu ji tu, carved in stone in 1136, maps rivers and coasts on a network of squares. In 1154 the scholar al-Idrisi completed a world map for King Roger II of Sicily, drawn with south at the top, as was common in Islamic mapmaking. In Korea, the Kangnido map of 1402 showed Africa, Europe and Asia together, decades before Portuguese ships rounded the Cape of Good Hope.

Medieval Europe's mappae mundi, such as the Hereford map of around 1300, placed Jerusalem at the centre and mixed geography with scripture and legend. Despite a stubborn modern myth, educated medieval Europeans knew perfectly well that the Earth was round. Pacific navigators made something entirely different: Marshall Islanders built stick charts from palm ribs and shells to show how ocean swells bend around islands.

In 1569 Gerardus Mercator published a projection on which a straight line was a constant compass bearing, ideal for sailors. The cost was distortion, because land near the poles swells dramatically.

Did you know? On a Mercator map Greenland looks about as large as Africa, but Africa is roughly fourteen times bigger.

National surveys, such as Britain's Ordnance Survey, founded in 1791, then measured whole countries by triangulation, and aerial photography and satellites followed in the twentieth century. Today GPS lets a phone place you within a few metres. Yet every map, from a clay disc to a navigation app, still decides what goes in the middle.

Codes and Codebreakers

A cipher scrambles the letters of a message according to a rule, the key; a code replaces whole words or phrases with symbols from a codebook. For as long as people have sent secrets, others have tried to read them, and the history of cryptography is a long contest between makers and breakers.

The Roman historian Suetonius records that Julius Caesar wrote confidential letters by shifting each letter three places along the alphabet, so that A became D. The Caesar cipher is easy to break once you suspect it, and the decisive weapon against such systems appeared in ninth-century Baghdad. The philosopher al-Kindi wrote a treatise on deciphering messages that describes frequency analysis: count how often each symbol appears, compare the result with the most common letters of the language, and the disguise falls away.

Renaissance Europe built a profession on secrets. In 1586 Mary, Queen of Scots, held captive in England, exchanged ciphered letters smuggled in beer barrels. Sir Francis Walsingham's decipherer, Thomas Phelippes, read them, and the evidence of the Babington Plot sent Mary to the block in 1587. In France, Antoine and Bonaventure Rossignol built Louis XIV's Great Cipher, which resisted attack until the cryptographer Étienne Bazeries cracked it in the 1890s.

Telegraph and radio made interception routine. In 1917 British codebreakers in Room 40 decoded the Zimmermann Telegram, in which Germany proposed an alliance with Mexico against the United States, helping to bring America into the First World War. The German Enigma machine scrambled letters through rotating wheels. Polish mathematicians Marian Rejewski, Jerzy Różycki and Henryk Zygalski first broke it in the 1930s and handed their methods to Britain and France in July 1939. At Bletchley Park, Alan Turing and Gordon Welchman designed electromechanical Bombes to find the daily settings, and Tommy Flowers built Colossus, an early electronic computer, to attack the Lorenz cipher of the German high command. In the Pacific, Navajo code talkers serving with the United States Marines passed messages in their own language that the enemy never broke.

Modern cryptography solved the oldest problem of all: how to agree a key with someone you have never met. In 1976 Whitfield Diffie and Martin Hellman published a method of public-key exchange, and the RSA system followed in 1977.

Did you know? Britain's GCHQ had secretly discovered public-key cryptography a few years earlier, through James Ellis, Clifford Cocks and Malcolm Williamson, but the work stayed classified until 1997.

Every online payment, messaging app and padlock icon in a browser rests on that mathematics. The contest goes on, with quantum computers now on the horizon, and the secret still belongs to whoever does the better arithmetic.

Barter, Debt and Gift

Every old economics textbook began with the same scene. A baker wants shoes, the shoemaker wants fish, and nobody can trade until money arrives to solve the "double coincidence of wants". Adam Smith sketched the story in The Wealth of Nations in 1776. The trouble is that anthropologists have spent more than a century looking for a society that actually ran on barter, and they have not found one. In 1985 the anthropologist Caroline Humphrey reviewed the evidence and concluded that no pure barter economy had ever been described.

What people did instead was keep track of what they owed. The earliest written accounts, clay tablets from Sumerian cities such as Uruk and Ur, are full of debt: barley lent at sowing and repaid at harvest, silver owed to temples and palaces, interest carefully recorded. Scribes measured value in silver by weight and in barley by volume, yet most deals never involved handing over either. Credit came before cash. Kings knew that debt could tear a society apart, so Babylonian rulers periodically proclaimed a mīšarum, an edict that cancelled certain debts and freed people who had been enslaved for them.

The third great system is the gift. In Argonauts of the Western Pacific (1922), Bronisław Malinowski described the kula ring of the Trobriand Islands and their neighbours off New Guinea, where men made long, risky canoe voyages to exchange shell valuables that nobody kept for long. In The Gift (1925), Marcel Mauss argued that no gift is ever free: it creates a duty to accept and a duty to give back, and those duties bind people together. On the Pacific Northwest coast of North America, the Kwakwaka'wakw and other nations held potlatch feasts at which hosts gave away great quantities of goods to show their rank. Canada banned the potlatch in 1885, and the ban was not lifted until 1951.

Did you know? In the kula ring, red shell necklaces travel clockwise around the island circuit while white shell armbands travel anticlockwise, so the two kinds of treasure pass each other endlessly.

Barter does exist, but mostly at the edges: between strangers who do not trust each other, or where money has broken down. Prisoners of war in the Second World War priced goods in cigarettes. Russian factories swapped goods with each other during the currency chaos of the 1990s, and neighbourhood barter clubs flourished in Argentina during its financial crisis of 2001 and 2002.

This matters because it changes what money is. Rather than a clever replacement for swapping, money looks more like a way of recording and settling obligations, which is why economists today describe most money as bank credit. Long before anyone struck a coin, people already owed each other, and they remembered.

The First Coins

A coin is a piece of metal of guaranteed weight and purity, stamped by an authority that vouches for it. Before coins, people paid in weighed silver, grain, cattle or cowrie shells, and in Mesopotamia silver changed hands by weight for two thousand years without anyone striking a coin. The stamp was the real invention: it let a stranger accept a payment without reaching for the scales.

The oldest known coins come from Lydia, a kingdom in western Anatolia, in what is now Turkey. Dozens were found in the foundation deposits of the Temple of Artemis at Ephesus, excavated for the British Museum in 1904 and 1905, and most scholars date them to around 630 to 600 BC. They are small, bean-shaped lumps of electrum, a natural alloy of gold and silver found in local rivers such as the Pactolus, stamped on one side with a design, often a roaring lion's head, and punched on the other. Herodotus, writing in the fifth century BC, says the Lydians were the first people to use coins of gold and silver, and tradition credits King Croesus with the first coins of pure gold and pure silver, though historians debate the details.

The idea spread quickly through the Greek world. Athens paid for its fleet and temples with silver "owls", coins stamped with the head of Athena and her owl, struck from silver mined at Laurion. They were trusted so widely that imitations circulated as far away as Arabia. Rome began issuing its silver denarius around 211 BC, and it remained the backbone of Roman pay for more than four centuries.

Coins were invented more than once. In China, bronze money shaped like small spades and knives circulated in the later Zhou period, and after the Qin unified China in 221 BC they imposed a single round coin, the banliang, with a square hole so that coins could be strung together. That shape lasted for more than two thousand years. In the Ganges valley of India, punch-marked silver coins, struck with several small symbols, appear by around the fifth century BC, and historians still debate how far Persian contact inspired them.

Did you know? The Chinese character for shell, 貝, appears inside many characters to do with value, such as 財 (wealth) and 貨 (goods), a fossil of the age when cowries served as money.

Coins also became the first mass medium. A ruler's portrait reached every market in the realm, and archaeologists now use coins to date layers, trace trade routes and unmask usurpers who minted their own. Mints still strike coins in vast numbers today, and the small stamped disc remains the most recognisable symbol of money itself.

Paper Money

Paper money is a promise you can spend. Unlike a gold coin, the note itself is worth almost nothing; its value rests entirely on trust in whoever issued it. That made it one of history's boldest financial experiments, and one of its most often abused.

China got there first. Under the Tang dynasty in the ninth century, merchants used "flying money", certificates that let them deposit cash in one city and collect it in another without hauling heavy strings of coins along the roads. In Sichuan, where the local currency was cumbersome iron coins, merchant houses in Chengdu began issuing paper deposit receipts called jiaozi. Around 1023 to 1024 the Song government took the business over and issued the world's first state paper money. We know the story from Song official histories and from the writings of officials who argued about how much to print.

The Mongol Yuan dynasty went further and made paper the main currency of an empire. Marco Polo described Kublai Khan's notes at length and was amazed that paper made from the inner bark of the mulberry tree could buy anything in the realm. The temptation was obvious: print more. Yuan notes, and then the Ming Da Ming baochao issued from 1375, were overissued until they lost most of their value, and by the fifteenth century the Ming economy had turned back to silver.

Europe came late. In 1661 the Stockholms Banco, founded by Johan Palmstruch, issued Europe's first banknotes, partly because Sweden's official copper "plate money" was so heavy. The bank printed too many and collapsed within a few years. The Bank of England, founded in 1694, issued notes promising to pay the bearer on demand, a phrase still printed on English notes today. In 1690 the colony of Massachusetts had already issued paper bills to pay soldiers, and the American colonies became keen experimenters with paper.

Did you know? Sweden's copper plate money, which helped push the country towards paper, included a ten-daler plate that weighed nearly 20 kilograms.

The history of paper money is also a history of inflation. Revolutionary France's assignats in the 1790s, Germany in 1923, when prices were doubling every few days, and Zimbabwe in 2008 all show what happens when governments print to pay their bills. Modern notes fight forgery with watermarks, security threads and, since Australia introduced the first in 1988, polymer plastic.

Today most money is not paper at all but numbers in bank ledgers, and the banknote is simply its most visible form. Each one still carries the same old bargain: a printed promise, honoured only as long as people believe it.

Banks and Bankers

A bank does two simple things that changed the world: it keeps other people's money safe, and it lends some of that money out. The gap between the two, deposits that can be withdrawn at any moment and loans that cannot easily be recalled, makes banking both powerful and fragile.

Lending is older than coins. In Mesopotamia, temples and palaces stored grain and silver and lent them out, and clay tablets record loans, interest and dates of repayment. The laws of Hammurabi, written around 1750 BC, already set limits on interest for grain and silver. In classical Athens, bankers called trapezitai sat at tables in the marketplace, changing foreign coins, taking deposits and lending to merchants. Speeches from Athenian lawsuits preserve their business in detail. In Rome, the argentarii did similar work around the Forum.

Did you know? Pasion, the richest banker in fourth-century BC Athens, began as a slave working at a banking table, was freed, and was eventually granted Athenian citizenship.

The word bank comes from the Italian banco, the bench or counter of medieval money changers, and Italian cities turned banking into an international business. The Medici Bank, founded in Florence in 1397 by Giovanni di Bicci de' Medici, ran branches in Rome, Venice, Geneva, Bruges and London. Its key tool was the bill of exchange, a written order to pay a sum in another city and another currency. Bills moved money across Europe without moving coins and, conveniently, let bankers earn a return without openly breaking the Church's rules against usury. The bank's ledgers and letters survive in Florentine archives, which is how historians can follow its rise and its collapse in 1494. Banca Monte dei Paschi di Siena, founded in 1472, still trades today.

Other traditions ran in parallel. Merchants across the Islamic world used written orders called suftaja to transfer funds between cities, and in India the hundi served as a bill of exchange for centuries. Northern Europe built public banks. The Bank of Amsterdam, opened in 1609, let merchants settle debts by transfer between accounts. Sweden's Riksbank, founded in 1668, is the oldest central bank still operating, and the Bank of England followed in 1694, created to lend money to the government for war with France.

Today central banks set interest rates and act as the lender of last resort when panic strikes, a role argued for by Walter Bagehot in Lombard Street in 1873. Most money in modern economies is created when ordinary banks make loans. From a Babylonian granary to a banking app, the job remains the same: keep promises, and lend wisely enough to keep them.

The Silk Roads

The Silk Roads were never a single road, and silk was only one of their cargoes. The name was coined in 1877 by the German geographer Ferdinand von Richthofen for the web of caravan routes that linked China with Central Asia, Persia, India and the Mediterranean. Few merchants travelled the whole distance. Goods passed from hand to hand and oasis to oasis, gaining value at every stop.

The traditional starting point is the journey of Zhang Qian, an envoy sent west by the Han emperor Wu around 138 BC to find allies against the nomadic Xiongnu. He was captured and held for about ten years, and came home with reports of Central Asian kingdoms and their famous horses. The Han soon pushed garrisons and watchtowers west through the Gansu corridor to Dunhuang, the gateway to the Taklamakan desert, whose caravans skirted the oases on its northern and southern edges. Exchange across Central Asia was older still, but Han interest turned it into a steady flow.

Some of the best evidence comes from the desert itself. In 1907 the archaeologist Aurel Stein found the Sogdian Ancient Letters in a ruined watchtower near Dunhuang: early fourth-century letters from merchants of Samarkand that were never delivered, describing trade and the chaos of war in China. At Dunhuang's Mogao caves, a library cave sealed around the year 1000 and reopened in 1900 held tens of thousands of manuscripts in Chinese, Tibetan, Sogdian, Sanskrit, Hebrew and other languages.

What moved? Westward went silk, lacquer and later paper and porcelain. Eastward came horses, glass, silver, wool, grapes and alfalfa. Ideas travelled too: Buddhism reached China along these routes, as did Christianity of the Church of the East, Manichaeism and later Islam. So did disease, for the Black Death crossed the steppe towards the Black Sea in the 1340s. Under the Mongol empire in the thirteenth century the routes were unusually safe, which is how Marco Polo could reach the court of Kublai Khan.

Did you know? China's monopoly on silk making was broken around 552, when, according to the Byzantine historian Procopius, monks smuggled silkworm eggs to the emperor Justinian in Constantinople.

The overland routes declined as ships carried more of the trade from the fifteenth century onwards. In 2014 UNESCO listed a long network of routes between Chang'an and the Tian Shan mountains as World Heritage, and modern Chinese infrastructure plans deliberately borrow the old name. The Silk Roads remind us that globalisation is not new; it simply used to travel at the speed of a camel.

Spices and the Sea

For most of history, some of the most valuable cargoes on Earth grew on a handful of tropical islands. Nutmeg and mace came only from the tiny Banda Islands in eastern Indonesia. Cloves grew on a few islands of the northern Moluccas, such as Ternate and Tidore. The best pepper came from the Malabar coast of south-west India, and cinnamon from Sri Lanka. Getting them to the kitchens and apothecaries of Europe, the Middle East and China was the work of sailors, merchants and the wind.

Did you know? When the pharaoh Ramesses II was mummified in 1213 BC, embalmers placed black peppercorns in his nostrils: pepper that must have travelled all the way from southern India.

By the first century AD, Greek and Roman ships sailed from Egypt's Red Sea ports to India. A Greek merchant's handbook, the Periplus of the Erythraean Sea, lists ports, goods and sailing seasons, and a papyrus of the second century records a loan for a cargo shipped from Muziris on the Malabar coast. Hoards of Roman coins found in southern India confirm the scale of the trade.

The secret was the monsoon. In the Indian Ocean the winds blow from the south-west in summer and from the north-east in winter, so a ship could sail out with one season and home with the next. That rhythm created a relay of ports. Spices moved from the islands to Malacca, across to Calicut and the Gujarat coast, then to Aden, up the Red Sea to Alexandria, and finally onto Venetian galleys that sold them across Europe. Arab, Gujarati, Tamil, Malay and Chinese merchants all took part. Between 1405 and 1433 the Ming admiral Zheng He led seven great fleets across the Indian Ocean as far as East Africa.

Europeans wanted to cut out the middlemen. In 1498 Vasco da Gama reached Calicut by sailing around the Cape of Good Hope, and in 1511 the Portuguese seized Malacca to control its strait. A century later the Dutch East India Company fought its way to a monopoly on nutmeg. In 1621 its governor-general, Jan Pieterszoon Coen, conquered the Banda Islands, and most of the Bandanese were killed, enslaved or driven out. At the Treaty of Breda in 1667 the Dutch kept the tiny nutmeg island of Run while the English kept New Amsterdam, soon renamed New York.

The monopolies did not last. Around 1770 the French administrator Pierre Poivre smuggled clove and nutmeg seedlings to Mauritius, and spices were soon grown across the tropics. As supply rose, spices slid from luxury to kitchen staple. The pepper grinder on your table is the quiet descendant of fleets, monsoons and empires.

Companies and Shares

A company that sells shares lets thousands of strangers pool their money in one venture, split the profits and, crucially, limit their losses. The idea sounds dull now, but it financed ocean fleets, railways and the modern corporation.

It had ancestors. Rome's societates publicanorum, partnerships that bid for state contracts such as tax collection, divided their capital into shares, though historians debate how freely these were traded. Medieval Italian merchants used the commenda, in which an investor funded a voyage and a travelling merchant ran it, and the two split the profit. In Sweden, a deed of 1288 records a bishop acquiring a one-eighth share in the copper mountain of Stora Kopparberg, often cited as the oldest known share document.

The decisive step came with the long-distance trading companies. The English East India Company received its royal charter on the last day of 1600, but at first it raised money voyage by voyage. In 1602 the Dutch merged rival firms into the Vereenigde Oostindische Compagnie, or VOC, granting it a monopoly on Dutch trade east of the Cape of Good Hope for twenty-one years. Its capital was meant to stay in the business for years at a time, so investors who wanted their money back had to sell their shares to someone else. A lively market grew on the Amsterdam exchange, from 1611 housed in a purpose-built bourse, complete with dividends, speculation and even early forms of short selling.

Did you know? The oldest known VOC share certificate, issued in 1606, was found in 2010 by a student researching in the archives of the Dutch town of Hoorn.

The VOC also shows the dark side of the idea. It was a private company with the right to wage war, sign treaties and govern territory, which it did from Batavia, now Jakarta, from 1619. Its English rival grew into the ruler of much of India until the British Crown took over its territories in 1858.

Shares soon spread from trade to everything else. Joint-stock companies dug Britain's canals and built its railways, and the Limited Liability Act of 1855 made it easy for investors to lose no more than they had put in. The Tokyo Stock Exchange opened in 1878, and stock markets are now found in most of the world's countries. Pension funds own slivers of thousands of firms on behalf of people who may never know it. Anyone with a pension is a partner in an idea first tested by Dutch merchants betting on nutmeg.

The Gold Standard

Under a gold standard, a country defines its money as a fixed weight of gold, and anyone holding its notes can, in principle, exchange them for gold at that rate. The promise was meant to stop governments printing money at will. For about a century it was the backbone of world finance, and it broke down twice.

Gold had been money for thousands of years, but usually alongside silver. Britain drifted onto gold almost by accident. In 1717 Isaac Newton, as Master of the Mint, set the value of the gold guinea against silver at a rate that overvalued gold, so silver coins were melted down or shipped abroad. The Coinage Act of 1816 made gold the legal standard, the gold sovereign appeared in 1817, and from 1821 Bank of England notes could again be exchanged for gold.

Other countries joined in the 1870s. The new German Empire switched to gold from 1871 to 1873, helped by the indemnity France paid after the Franco-Prussian War, and the United States effectively followed, confirmed by the Gold Standard Act of 1900. Not everyone was happy. In 1896 William Jennings Bryan, who wanted silver to back the dollar too, told the Democratic convention: "You shall not crucify mankind upon a cross of gold." Even so, for a few decades fixed exchange rates and London's central role let trade and investment flow with unusual ease.

The First World War broke the system, as governments suspended convertibility to pay for the fighting. Britain returned in 1925 at the pre-war rate, a decision John Maynard Keynes attacked in The Economic Consequences of Mr Churchill. The strong pound hurt exports, and Britain left gold again in 1931. Many economic historians argue that the countries which clung to gold longest suffered most in the Great Depression. In 1933 the United States ordered its citizens to hand in most of their gold coins and bullion.

After the Second World War, the Bretton Woods agreement of 1944 built a gold-exchange system: other currencies were pegged to the US dollar, and the dollar could be converted into gold by foreign central banks. As dollars piled up abroad, the promise became impossible to keep. On 15 August 1971 President Richard Nixon closed the "gold window", and by 1973 the major currencies floated freely.

Did you know? The gold sovereign first struck in 1817 is still minted today, and most carry Benedetto Pistrucci's design of St George slaying the dragon.

No country now ties its money to gold, yet central banks still keep vast stores of it, much of it in vaults beneath the Bank of England and the Federal Reserve Bank of New York. Gold no longer anchors money, but it remains what nervous people buy when they stop trusting paper.

Crashes and Bubbles

A bubble forms when prices rise far above any sensible estimate of value because buyers expect to sell to someone else at a higher price. A crash is the moment that belief fails. The pattern repeats so faithfully that the economic historian Charles Kindleberger, building on the work of Hyman Minsky, laid out its stages in Manias, Panics, and Crashes in 1978: a new opportunity, a boom fed by easy credit, euphoria, distress and finally panic.

The most famous early case is tulip mania in the Dutch Republic, which peaked and broke in February 1637. Popular accounts, many drawn from Charles Mackay's Extraordinary Popular Delusions of 1841, describe a nation ruined by flowers. Historians who have worked through the Dutch notarial archives, notably Anne Goldgar, argue that the mania was real but small, confined to a limited circle of buyers, and caused few bankruptcies. The legend proved far more durable than the bulbs.

The year 1720 brought two bubbles at once. In France the Scottish financier John Law's Mississippi Company, tied to his scheme of paper money, collapsed. In London, shares in the South Sea Company soared and then crashed, ruining many investors and prompting Parliament to pass the Bubble Act. Isaac Newton, then Master of the Mint, is reported to have lost a large sum.

Did you know? In AD 33 Rome suffered a credit crisis: according to Tacitus, a crackdown on lending set off a rush to call in loans, and the emperor Tiberius ended the panic by offering interest-free loans through the banks.

Bigger markets brought bigger crashes. On Black Thursday, 24 October 1929, and Black Tuesday, 29 October, prices on the New York Stock Exchange collapsed, and the failure of thousands of American banks over the next few years helped turn a crash into the Great Depression. Japan's land and share bubble burst after the Nikkei index peaked at the end of 1989, leaving a "lost decade" of slow growth. The dot-com bubble burst in 2000. In 2008 falling American house prices wrecked the value of mortgage-backed securities, and on 15 September Lehman Brothers filed for the largest bankruptcy in US history, spreading panic through banks around the world.

Each crash produced new rules: the US Securities and Exchange Commission in 1934, deposit insurance to stop bank runs, and tougher capital requirements for banks after 2008. Historians of finance note that the rules tend to be relaxed again once memories fade. Bubbles are less a form of madness than optimism with borrowed money, and every generation seems to learn that for itself.

From Cards to Contactless

Most money now moves without anything physical changing hands. A payment card is a key to an account, and a contactless tap is a brief conversation between computers about who owes whom. The story runs from cardboard to radio chips in about seventy years.

Credit itself is ancient, and shops had always kept tabs. In the early twentieth century, American department stores and oil companies gave loyal customers metal charge plates and cards. The first general-purpose charge card was Diners Club, launched in New York in 1950. The tale that founder Frank McNamara dreamed it up after forgetting his wallet at dinner was, according to the company's own early publicist, invented for publicity. In 1958 Bank of America mailed some 60,000 unsolicited BankAmericards to households in Fresno, California, creating the first mass revolving credit card, which later became Visa. Britain's first credit card, Barclaycard, arrived in 1966.

Cash went electronic too. On 27 June 1967 Barclays opened the world's first cash machine at its branch in Enfield, north London, and the comedy actor Reg Varney made the first withdrawal. Magnetic stripes, developed at IBM in the 1960s, let machines read cards, and France pioneered cards with microchips in the 1980s. The United Kingdom made chip and PIN the standard in 2006, ending the era of signing receipts.

Did you know? The first cash machine did not use plastic cards at all: customers fed in paper vouchers marked with carbon-14, a slightly radioactive substance that the machine could detect.

Contactless cards use a radio chip that works only within a few centimetres of the reader, and UK banks launched them in 2007. The same year in Kenya, Safaricom launched M-Pesa, which let people send money by text message from simple mobile phones, and it spread across East Africa long before most Europeans paid with a phone. China leapt from cash to QR codes with Alipay and WeChat Pay, and India's UPI system, launched in 2016, now carries a vast share of everyday payments.

Each tap sets off a chain. The terminal sends a request to the shop's bank, the card network routes it to the customer's bank, and an answer comes back within seconds. Behind the beep lies a vast settlement system that moves the actual money later, in bulk. The convenience raises new questions about privacy, fees and people who are left behind, and Sweden, one of the most cashless countries, has passed laws to keep cash services available. Money has travelled from clay tablets to radio waves, and it is still, at heart, a record of who owes what.

Walls and Fortifications

A fortification is an argument made in stone, earth or timber: it says that taking this place will cost more than it is worth. People have been making that argument for at least ten thousand years, and the remains of their walls are among the largest objects humans have ever built.

The oldest candidate stands at Jericho, in the West Bank. Digging there in the 1950s, the archaeologist Kathleen Kenyon uncovered a stone wall and a solid round tower about 8 metres high, raised around 8000 BC by people who had only recently begun to farm. Radiocarbon dates from the surrounding layers fix its age, but its purpose is less certain. Kenyon saw defence; later scholars have argued for flood protection, or a monument that bound the community together. Historians still debate it, a useful reminder that a wall is not always a fortress.

By the third millennium BC, city walls were normal across Mesopotamia. The Epic of Gilgamesh opens by inviting the reader to walk the walls of Uruk and admire their brickwork, and archaeologists have traced a circuit roughly 9 kilometres long. In China, builders rammed layers of earth into wooden frames to make long frontier walls, which the Qin dynasty linked after 221 BC. Most of the Great Wall that tourists walk today is far younger, built in brick and stone by the Ming dynasty after 1368. A Chinese survey published in 2012 measured all the walls, of every period, at 21,196 kilometres.

Walls did different jobs in different places. Hadrian's Wall, begun in AD 122, ran about 117 kilometres across northern Britain and controlled the movement of people and goods as much as it stopped raiders. Constantinople's Theodosian Walls, completed in the 410s, layered a moat, an outer wall and a taller inner wall, and kept attackers out for a thousand years until Ottoman cannon breached them in 1453. In southern Africa, the dry-stone enclosures of Great Zimbabwe, raised without mortar between the 11th and 15th centuries, displayed royal power more than they repelled armies.

Gunpowder forced a redesign. Tall walls shattered under cannon fire, so Italian engineers of the early 1500s built low, thick ramparts with angled bastions that let defenders sweep every approach with fire. This trace italienne, or star fort, spread from Malta to the Caribbean, and in France Sébastien Le Prestre de Vauban built or remodelled scores of fortresses for Louis XIV. In the 1930s France tried once more with the Maginot Line, a chain of concrete forts that largely worked as designed in 1940, when German armour simply went round it through the Ardennes.

Did you know? The Great Wall of China cannot be seen from the Moon with the naked eye, and China's first astronaut, Yang Liwei, said in 2003 that he could not make it out from orbit either.

Walls still rise along borders today, and they still make the same old promise. Their long history suggests a humbler truth: a wall buys time, and what matters is what its builders do with it.

The Horse in War

For most of recorded history the fastest thing on a battlefield was a horse. Mounted warriors could scout, raid, chase and charge, and the peoples who mastered them, from the steppe nomads to the Comanche, fought far above their numbers. The war horse was the tank, the lorry and the reconnaissance aircraft of the pre-industrial world, all rolled into one nervous animal.

Exactly when horses were tamed is still argued over. Worn teeth and traces of mare's milk in pots at Botai, in Kazakhstan, point to people managing horses around 3500 BC, but the Botai animals turned out to be ancestors of Przewalski's horse. Ancient DNA published in 2021 showed that today's domestic horses descend from a lineage that spread from the western steppe, near the Volga and Don rivers, only around 2200 BC. That spread coincides with the first spoked-wheel chariots, found buried with their owners at Sintashta sites in Russia from around 2000 BC.

Chariots dominated warfare across the Near East, Egypt, India and Shang China for centuries. At Kadesh, in Syria, around 1274 BC, Ramesses II and the Hittite king Muwatalli II fought one of the largest chariot battles ever recorded, an inconclusive clash that Ramesses carved on temple walls as a triumph. Fighting from the horse's back took longer to master. Assyrian reliefs of the 9th century BC show mounted archers working in pairs, one rider holding both sets of reins while the other shot, and by the time of the Scythians, horse archers had become the terror of settled empires.

Better equipment slowly changed what riders could do. Paired stirrups appear in China by the early 5th century AD; one of the oldest surviving sets comes from the tomb of the Northern Yan nobleman Feng Sufu, who died in 415. They reached Europe by the 8th century. The historian Lynn White argued in 1962 that stirrups created feudalism by making the charging knight possible, a thesis most historians now reject as far too neat. On the steppe, Mongol armies of the 13th century gave each rider several remounts, letting them cover distances that astonished their enemies.

Horses also remade whole societies. Spanish ships brought them back to the Americas from 1493, where native horses had died out thousands of years earlier, and Hernán Cortés used a handful of them to frightening effect in Mexico in 1519. Within two centuries, peoples of the Great Plains such as the Comanche and Lakota had built new ways of life around horses taken or traded from Spanish settlements. Machine guns and barbed wire ended the massed charge on the Western Front, yet horses hauled guns and supplies through both world wars, and the German army of 1939 depended on them far more than its newsreels admitted.

Did you know? The famous image of Polish cavalry charging German tanks in 1939 is a myth; it grew from a charge at Krojanty against German infantry, cut short when armoured cars opened fire.

The horse left the battlefield only when engines could do everything it did, and not a day sooner.

Armour and the Knight

Armour is a trade-off written in metal: every gram that stops a blade also slows a body. For three and a half thousand years, smiths across the world have tried to strike that balance, and the knight in full plate became Europe's most famous answer.

The oldest near-complete suit in Europe was found in 1960 in a tomb at Dendra, near Mycenae in Greece. Dating to around 1400 BC, it is a set of bronze plates that enclosed the wearer from neck to thigh, found with a helmet faced in boar's tusk. Experiments with replicas suggest it could be worn in real fighting, not just on parade.

Iron mail, a mesh of thousands of interlinked rings, was probably invented by Celtic smiths by the 3rd century BC, and Rome adopted it widely. Roman legionaries also wore the strip armour now called lorica segmentata, fragments of which turned up at Kalkriese in Germany, site of the Roman disaster of AD 9. In East Asia, armourers laced small scales of iron or lacquered leather into flexible lamellar coats, culminating in the boxy ō-yoroi of Japan's mounted samurai archers from around the 10th century.

In medieval Europe, the mounted warrior of the 11th century wore a mail shirt, or hauberk, as the Bayeux Tapestry shows. Plates were added piece by piece over the 13th and 14th centuries, and by around 1420 the full harness of jointed steel had arrived. Workshops in Milan and southern Germany sold suits across Europe, and later armourers proved breastplates by firing a pistol at them, leaving the dent as a guarantee. A complete field harness usually weighed around 15 to 25 kilograms, spread over the whole body, which is less than many modern infantry packs.

The knight himself was a social rank more than a type of soldier: a man of landed family, dubbed in a ceremony and expected to follow the ideals of chivalry. Gunpowder did not abolish armour overnight. Cuirassiers still wore steel breastplates at Waterloo in 1815, and steel helmets returned to the trenches in 1915. The fibre Kevlar, invented by the chemist Stephanie Kwolek in 1965, now stiffens the body armour worn by police and soldiers worldwide.

Did you know? Knights were not winched onto their horses by cranes; the image owes much to Laurence Olivier's 1944 film of Henry V, while real knights could mount, run and get up from the ground unaided.

The materials changed from bronze to Kevlar, but the bargain between protection and movement has never gone away.

Gunpowder Changes Everything

Gunpowder is a simple mixture of saltpetre, charcoal and sulphur that burns fast enough to throw a ball through a wall. It reshaped fortresses, armies, empires and tax systems, which is a great deal of consequence for something that could be mixed in a bowl.

It began in China. A Daoist alchemical text of the 9th century warns that heating saltpetre, sulphur and honey together had burned people's hands and faces and even set houses alight. The earliest surviving written formulas appear in the Wujing Zongyao, a military manual compiled for the Song court in 1044, which describes incendiary bombs hurled by catapult. Song armies then developed the fire lance, a bamboo or paper tube that spat flame and shrapnel, and by the late 13th century true metal guns existed: a bronze hand cannon found in Heilongjiang is dated to around 1288 by the campaign it is linked with.

The knowledge travelled west, quite possibly with the Mongols. Europe's oldest picture of a gun is in a manuscript made for the young Edward III by Walter de Milemete in 1326, showing a vase-shaped barrel firing a large bolt. Within a century guns were big enough to matter. In 1453 Sultan Mehmed II brought giant bombards, cast by a founder named Orban, against the walls of Constantinople, and they helped end a city that had resisted siege for a thousand years.

Firearms then spread across continents with startling speed. Babur used matchlocks and field guns to win the battle of Panipat in 1526 and found the Mughal Empire. Portuguese traders brought matchlocks to the island of Tanegashima in Japan in 1543, and Japanese smiths were soon copying them in great numbers. At Nagashino in 1575, Oda Nobunaga's massed gunners broke the famous Takeda cavalry, though historians debate the legend of perfectly rotating volley fire. Marshall Hodgson and William McNeill later called the Ottoman, Safavid and Mughal states the gunpowder empires, a label still argued over.

Guns also fed what historians, since Michael Roberts coined the phrase in 1955, call the military revolution. Star forts, larger infantry armies and costly artillery trains pushed states to tax and borrow more, and the gun-armed sailing ship carried European power across the oceans. In 1884 the French chemist Paul Vieille produced Poudre B, a smokeless powder that ended the era of battlefields wreathed in white smoke.

Did you know? The standard black powder recipe, roughly 75 parts saltpetre to 15 parts charcoal and 10 parts sulphur, stayed in use for centuries and still lifts fireworks into the sky today.

A discovery made in alchemists' workshops became the great leveller of the battlefield, and it rarely levelled anything gently.

Navies and Sea Power

A navy is a fleet kept by a state for war, and sea power is what that fleet buys: control of trade, coasts and the movement of armies. Whoever commands the sea can choose where to fight, a simple idea that has decided the fate of empires.

The earliest surviving picture of a sea battle is carved on the temple of Ramesses III at Medinet Habu, in Egypt. Made around 1175 BC, it shows Egyptian ships grappling with the vessels of the Sea Peoples while archers shoot from the decks. Other evidence comes from wrecks, ship sheds and texts. Athenian triremes, with three banks of oarsmen and a bronze ram at the bow, beat the Persian fleet at Salamis in 480 BC, and a full-size working replica, Olympias, was launched in 1987 to test how they handled.

Rome, a land power, learned fast: in the First Punic War against Carthage it fitted ships with the corvus, a boarding bridge that turned sea fights into infantry battles. In Asia, the Ming admiral Zheng He led seven great voyages across the Indian Ocean between 1405 and 1433, although historians debate how big his treasure ships really were. In 1592 the Korean admiral Yi Sun-sin used armoured turtle ships and bold tactics to cut Japanese supply lines and cripple an invasion.

The gun-armed sailing ship changed the game. At Lepanto in 1571, the last great clash of oared galleys, a Christian coalition defeated an Ottoman fleet. Seventeen years later, English ships with longer-range guns harried the Spanish Armada up the Channel before storms wrecked much of it. The disciplined line of battle produced Trafalgar in 1805, after which Britain's navy policed the world's sea lanes for a century. In 1890 the American officer Alfred Thayer Mahan published The Influence of Sea Power upon History, which was read eagerly in London, Berlin and Tokyo and helped fuel a naval arms race.

Steel and steam came next. HMS Dreadnought, launched in 1906 with ten big guns and steam turbines, made every older battleship obsolete at a stroke. Then aircraft took over. In the battles of the Coral Sea and Midway in 1942, carriers struck at each other from far beyond the horizon, and the battleship lost its crown. Most of the world's trade still travels by sea, and navies still guard the narrow straits it must pass through.

Did you know? At the Battle of the Coral Sea in May 1942, the opposing fleets never came within sight of each other; it was the first naval battle fought entirely by aircraft.

The ships have grown from rowed hulls to floating airfields, but the prize is unchanged: the freedom to use the sea, and the power to deny it to others.

Sieges

A siege is war reduced to patience: an army surrounds a fortified place and tries to break in, starve it out or simply wait for it to give up. Because walled towns held the food, wealth and people that mattered, sieges were for most of history the commonest form of serious war, far commoner than pitched battles.

Some of the earliest evidence comes from Hamoukar in northern Syria, where excavators found a town wrecked around 3500 BC, its ruins littered with clay sling bullets. The clearest picture comes much later. In 701 BC the Assyrian king Sennacherib besieged Lachish in Judah, then decorated his palace at Nineveh with reliefs of the assault: archers, battering rams pushed up a ramp, and captives led away. The reliefs are now in the British Museum, and archaeologists have found the Assyrian siege ramp itself at Lachish, along with the defenders' counter-ramp behind the wall.

Siege craft became an engineering profession. In AD 73 or 74 the Romans ringed the desert fortress of Masada with a wall and piled a huge ramp up its western side. Chinese engineers developed the trebuchet, a throwing arm pulled by teams of people, before 300 BC; the heavier counterweight trebuchet appeared in the Mediterranean world in the 12th century. In 1273 the Mongols ended their long siege of the Chinese city of Xiangyang with counterweight machines built by two Muslim engineers sent from Persia.

Underneath the walls a quieter war went on. Attackers dug mines to bring down towers, and defenders counter-mined to meet them in the dark. Gunpowder turned mines into bombs and cannon into wall-breakers. From the late 1600s the French engineer Sébastien de Vauban made attack a near-science, approaching a fortress with zigzag trenches and parallel lines that his troops dug step by step, as at Maastricht in 1673.

Starvation was always the cheapest weapon. The siege of Leningrad lasted 872 days, from September 1941 to January 1944, and hundreds of thousands of civilians died, most of them from hunger and cold. Sarajevo endured nearly four years of encirclement in the 1990s, its people dodging snipers to fetch water.

Did you know? The Roman siege ramp at Masada, built nearly two thousand years ago, still climbs the western side of the rock, and visitors walk up a path along it today.

Walls, machines and explosives all changed, but the question at the heart of every siege stayed the same: who runs out first?

Total War

Total war is war that claims everything a society has: its young men and women, its factories, farms, money, science and imagination. Civilians become workers in the war effort and therefore, in the eyes of the enemy, targets. The phrase is modern, and historians argue about how far back the thing itself goes.

Ancient and medieval wars could be devastatingly thorough. Rome razed Carthage in 146 BC, the Mongols destroyed cities that resisted them, and the Thirty Years' War of 1618 to 1648 emptied whole districts of the German lands. Yet such wars were fought by limited armies, raised and paid by rulers who could not command every resource of their subjects. The turning point came with the French Revolution. On 23 August 1793 the National Convention decreed the levée en masse, placing every French citizen at the service of the war: young men to fight, married men to forge weapons, women to make tents and clothing, children to turn old linen into bandages.

Industry multiplied the effect. Britain had already introduced income tax in 1799 to pay for its wars with France. In the American Civil War, railways, telegraphs and factories fed huge armies, and in 1864 General William T. Sherman marched through Georgia destroying railways, farms and stores to break the South's ability to fight. The Prussian theorist Carl von Clausewitz had described war's pull toward the absolute in On War, published in 1832, though he stressed that politics normally holds it back.

The two world wars made total war the norm. Between 1914 and 1918 governments introduced conscription, rationing, censorship and state control of industry, and women took on work in munitions factories, farms and transport across the warring nations. The German general Erich Ludendorff gave the idea its name in his 1935 book Der totale Krieg. In February 1943 Joseph Goebbels asked a Berlin crowd, "Do you want total war?" From the Blitz to the firebombing of Tokyo and the atomic bombs dropped on Hiroshima and Nagasaki in August 1945, the line between the front and the home front almost vanished.

Total war also built the modern state. Planning ministries, research laboratories, welfare schemes and higher taxes often grew out of wartime mobilisation, and many of them outlived the peace that followed.

Did you know? Britain's food rationing, begun in January 1940, did not fully end until July 1954, nearly nine years after the Second World War was over.

Total war made everyone a participant, which is precisely why it proved so hard to limit and so terrible to endure.

Rules of War: from Chivalry to Geneva

Every culture that has fought has also tried to set limits on fighting: who may be killed, how prisoners are treated, which places are sacred. The laws of war have often been broken, yet they have grown from customs and codes of honour into treaties accepted by every state on Earth.

Ancient texts show the impulse. The Indian Laws of Manu forbid a warrior to strike an enemy who has surrendered, is asleep or has lost his armour. The Chinese Art of War urges that captured soldiers be treated kindly and kept. Early Islamic tradition records the caliph Abu Bakr instructing his armies not to kill women, children or the elderly, nor to cut down fruit trees. Such rules were also practical: mercy made enemies more willing to surrender.

In medieval Europe the Church tried to tame its own warrior class. The Peace of God, proclaimed at a council at Charroux in 989, protected clergy, peasants and their property, and the Truce of God of the 11th century banned fighting on certain days of the week. Chivalry added a code of honour, largely for knights' dealings with each other: a captured noble was ransomed, while common soldiers were often killed. In 1625 the Dutch jurist Hugo Grotius published On the Law of War and Peace, arguing that law bound states even in war.

The modern system began with one man's horror. In 1859 the Swiss businessman Henry Dunant saw thousands of wounded men left to suffer after the battle of Solferino in northern Italy. His book A Memory of Solferino led to the founding of the International Committee of the Red Cross in 1863 and, in August 1864, to the first Geneva Convention, which protected wounded soldiers and the medics who treated them. In 1863, too, the Union army in the American Civil War issued the Lieber Code, setting out rules for its soldiers' conduct. Conferences at The Hague in 1899 and 1907 restricted certain weapons and methods of fighting.

The Second World War showed how little those rules had restrained. The Nuremberg trials of 1945 and 1946 established that individuals could be punished for war crimes, and the four Geneva Conventions of 1949 extended protection to prisoners of war and civilians. Additional Protocols followed in 1977, and in 1998 the Rome Statute created the International Criminal Court, which opened in 2002.

Did you know? The Geneva Conventions of 1949 have been ratified by every state in the world, 196 in all, making them among the most widely accepted treaties ever written.

The laws of war cannot prevent war, but they draw a line, and they make crossing it a crime with a name.

Spies and Intelligence

Intelligence is knowledge about an enemy that the enemy would rather you did not have, and spies are the people who fetch it. It is one of the oldest trades in war and one of the least documented, because its best practitioners work hard to leave no trace.

The earliest accounts come from texts. Letters from the palace archive at Mari, in Syria, written in the 18th century BC, pass on reports about the movements of rival kings and their troops. The Hebrew Bible tells of Moses sending twelve spies into Canaan, and of the two spies at Jericho hidden on a roof by Rahab. In China, the Art of War, traditionally attributed to Sun Tzu, ends with a chapter on the use of spies that names five kinds, including the double agent, and India's Arthashastra describes a state network of informers disguised as ascetics, merchants and students.

Spying became state business in early modern Europe. Sir Francis Walsingham, Elizabeth I's principal secretary, ran agents across Europe, and in 1586 his decipherer Thomas Phelippes read the secret letters of the Babington Plot, evidence that led to the execution of Mary, Queen of Scots, in 1587. During the American Revolution, George Washington's Culper Ring smuggled reports out of British-held New York from 1778, using invisible ink and numbered code words.

The 20th century industrialised secrets. Mata Hari, shot by France in 1917, became the legendary seductress-spy, though historians doubt she ever passed on anything of much value. In the Second World War, Britain's Double Cross System controlled the German agents sent to Britain, and the Spanish double agent Juan Pujol García, codenamed Garbo, helped convince Hitler that the Normandy landings of 1944 were only a diversion. Spies betrayed their own side too: the Cambridge Five passed British secrets to Moscow for years.

Then the cameras went up. An American U-2 spy plane was shot down over the Soviet Union on 1 May 1960, and that August a capsule from the Corona satellite brought back the first photographs of the Soviet Union taken from orbit. Today satellites, intercepted signals and a flood of public information, from ship trackers to social media posts, sit alongside the oldest method of all: a person who knows something, persuaded to tell.

Did you know? The first army to spy from the air was French: at the Battle of Fleurus in 1794, observers in the balloon L'Entreprenant watched Austrian troop movements and sent down reports.

The tools have changed from whispers to satellites, but intelligence still comes down to a very old question: whom do you trust?

Making Peace: Treaties and Truces

Ending a war is often harder than starting one. A truce stops the fighting for a time; a treaty tries to settle what the fighting was about. Both depend on something no weapon can supply: each side's belief that the other will keep its word.

The oldest record of a peace settlement is carved on the Stele of the Vultures from Girsu, in southern Iraq, made around 2450 BC, on which King Eannatum of Lagash makes the men of rival Umma swear oaths before the gods to respect a border. The most famous ancient treaty came around 1259 BC, when Ramesses II of Egypt and Hattusili III of the Hittites agreed peace and mutual support. Both versions survive: the Egyptian in hieroglyphs on temple walls at Karnak, the Hittite in Akkadian cuneiform on clay tablets from Hattusa in Turkey. A replica of one tablet hangs at the United Nations headquarters in New York.

Treaties grew more elaborate as states did. The Peace of Westphalia of 1648 ended the Thirty Years' War after years of talks in Münster and Osnabrück, and is often credited with founding the modern system of sovereign states, though many historians now see that as an exaggeration. In 1689 Russia and Qing China signed the Treaty of Nerchinsk, with Jesuit priests interpreting and the official text in Latin. In New Zealand, the Treaty of Waitangi of 1840 had English and Māori texts that said different things, a gap that is still being worked through today.

Peace can be well or badly made. The Congress of Vienna of 1815 kept a rough balance among the great powers for decades, while the Treaty of Versailles of 1919 left Germany resentful, and historians still debate how far it led to the next war. Sometimes no treaty comes at all: the fighting in Korea stopped with an armistice on 27 July 1953, and no peace treaty has followed. The Good Friday Agreement of 10 April 1998, approved by voters on both sides of the Irish border, offers another model, built on power-sharing and patient compromise.

Small truces matter too. At Christmas 1914, soldiers along parts of the Western Front climbed out of their trenches to exchange gifts and bury their dead, until officers put a stop to it.

Did you know? The Korean War has never formally ended; the 1953 armistice was signed by military commanders, and South Korea's government never signed it at all.

Treaties are promises written down, and the best of them make keeping the promise easier than breaking it.

Chiefs, Kings and Pharaohs

Long before anyone wrote a law down, someone was in charge. Anthropologists describe a ladder of authority: small bands that decide things together, chiefdoms in which one family holds hereditary rank, and states in which a king commands officials, soldiers and taxes. The ladder is a model rather than a rule, but it helps explain how a village headman became, in a few places, a god on earth.

The first traces are in graves. At Varna, on Bulgaria's Black Sea coast, a cemetery of around 4500 BC held one man buried with gold ornaments and a sceptre-like axe, while most of his neighbours took almost nothing with them: rank, made visible in metal. Around 3100 BC the Narmer Palette, a carved slab of siltstone found at Hierakonpolis in 1898, shows an Egyptian ruler wearing the white crown of the south on one side and the red crown of the north on the other. Historians debate whether it records a real conquest, but it is an early manifesto of kingship.

Egypt's answer to the question "by what right?" was religion. The pharaoh was the living Horus, responsible for ma'at, the cosmic order that kept the Nile flooding and the sun rising. In Mesopotamia the Sumerian word lugal simply meant "big man", and the Sumerian King List opens with kingship descending from heaven. In China the Zhou, who overthrew the Shang around 1046 BC, proclaimed the Mandate of Heaven: Heaven granted power to a virtuous ruler and withdrew it from a wicked one, which conveniently justified every successful rebellion that followed.

Other societies found other anchors. In Hawaii the ali'i chiefs traced their descent from the gods and were protected by strict kapu rules. Around 1700 the Asante of West Africa united under Osei Tutu around the Golden Stool, which tradition says came down from the sky; it belongs to the nation rather than the king, and nobody sits on it. In Europe, James VI and I argued for the divine right of kings, a theory his son Charles I took with him to the scaffold in 1649.

Did you know? The word pharaoh comes from the Egyptian per-aa, "great house", meaning the palace; it only came to mean the king himself around the reign of Thutmose III, in the fifteenth century BC.

Monarchy has not vanished. Several dozen countries still have a king, queen, emperor, sultan or emir, though most of them reign within a constitution rather than rule. What survives is the ancient bargain at the heart of every crown: power needs a story about why it deserves to be obeyed.

Hammurabi and the First Written Laws

A law that lives only in memory can be bent by whoever remembers it. Writing it down changes the argument: now the rule exists outside the ruler, on a surface that anyone who can read may point to. The most famous early attempt is the Code of Hammurabi, issued by the king of Babylon around 1754 BC, near the end of his long reign.

We know it from a single spectacular object. In 1901 and 1902, French archaeologists digging at Susa in south-western Iran found a black basalt stele about 2.25 metres tall. At the top, a carved relief shows Hammurabi standing before Shamash, the sun god of justice. Below run columns of cuneiform: a boastful prologue, around 282 laws and an epilogue inviting any wronged man to have the stele read to him. The stone had travelled. An Elamite king, Shutruk-Nakhunte, carried it off from Babylonia as war booty in the twelfth century BC, and it is now in the Louvre.

Hammurabi was not first. Fragments survive of the laws of Ur-Nammu of Ur, from around 2100 BC, and of Lipit-Ishtar of Isin, from around 1930 BC. All share the same pattern: if this happens, then that follows. Hammurabi's laws cover theft, trade, wages, marriage, inheritance, surgery and building. A builder whose house collapses and kills the owner is to be put to death. The famous "eye for an eye" is there too, but punishment depended on status: destroying a nobleman's eye cost you your own, while destroying a commoner's cost a fine in silver.

Did you know? A smooth band near the bottom of the stele's front marks where several columns of laws were scraped away, probably by the Elamites who took it to Susa; scholars restore some of the gap from clay tablet copies.

Historians debate what the code was for. Thousands of Old Babylonian contracts and lawsuit records survive, yet they almost never cite it. Many scholars now read it as a royal showcase of wise judgements, part law and part propaganda, rather than a statute book that judges consulted. Similar ambitions appear far away and later. In Athens, Draco wrote down laws around 621 BC that became a byword for severity. In China, bamboo slips found at Shuihudi in 1975 preserve Qin legal texts from the third century BC, and the Tang Code of the seventh century shaped law across East Asia for centuries.

The idea outlived Babylon. Every published statute, from a parish by-law to a national constitution, follows Hammurabi's gamble: once the rules are written down, even rulers can be measured against them.

Democracy in Athens

Democracy, from the Greek demos, the people, and kratos, power, was not invented as a theory. It was improvised in Athens after 508 BC, when the aristocrat Cleisthenes, backed by a popular uprising, reorganised the citizens into ten new tribes that cut across old family loyalties. For the next two centuries, with interruptions, the citizens governed themselves directly.

Direct really meant direct. The Assembly, or ekklesia, met dozens of times a year on the Pnyx, a rocky hillside west of the Acropolis, where any citizen could speak and thousands voted by show of hands on war, peace, taxes and treaties. Its agenda was prepared by the Council of 500, fifty men from each tribe, chosen by lot for a year. Lot, not election, filled most offices, because Athenians thought elections favoured the rich and the famous. Generals, whose mistakes could lose a war, were the great exception: they were elected, and Pericles was chosen again and again.

The evidence is unusually tangible. In the Agora archaeologists have found fragments of a kleroterion, a stone allotment machine with rows of slots for citizens' bronze identity tickets and a tube that released black and white balls to decide who served. They have also found thousands of ostraka, broken pottery sherds scratched with names. Once a year the Assembly could vote to exile one man for ten years; sherds survive naming Themistocles, Aristides and Xanthippus, the father of Pericles. Courts were run by citizen juries of 201, 501 or more, paid a small daily fee from the middle of the fifth century BC.

Did you know? About 190 ostraka found in a well on the north slope of the Acropolis all bear the name of Themistocles, yet they were written by only a handful of hands, which suggests that ballots were prepared in advance and handed out.

It was a democracy with sharp edges. Only adult male citizens took part, a few tens of thousands at most, while women, enslaved people and resident foreigners, the metics, were excluded. A citizen jury of around 500 sentenced the philosopher Socrates to death in 399 BC, and Plato never forgave the many for it. After Macedon defeated Athens in 322 BC, the system was dismantled.

Later ages borrowed the word long before they borrowed the practice. Most modern democracies are representative rather than direct, but Athenian tools keep returning. In Ireland, assemblies of randomly chosen citizens helped shape the referendums on same-sex marriage in 2015 and on abortion in 2018. The lottery, it turns out, was not such a quaint idea after all.

The Roman Republic and Its Law

According to Roman tradition, in 509 BC the people of Rome expelled their last king, Tarquin the Proud, and swore never again to be ruled by one man. What replaced him was the Republic, from res publica, "the public thing": a balance of elected magistrates, an aristocratic Senate and popular assemblies that lasted for nearly five centuries.

Power was divided and time-limited. Two consuls, elected each year, commanded the armies and could block each other. The Senate, made up of former magistrates, had no formal power to legislate but enormous authority, and its advice usually got its way. Citizen assemblies elected officials and passed laws. After the plebeians, the common citizens, walked out of the city in protest in 494 BC, they won officers of their own, the tribunes, who could stop almost any act with a single word: veto, "I forbid". The Greek historian Polybius admired the mix as a near-perfect constitution.

Roman law began with a public notice. Around 450 BC a commission wrote down the Twelve Tables, displayed in the Forum so that the patrician elite could no longer keep the rules to themselves. The tablets themselves were lost, and we know them only from quotations by later writers; Cicero recalled learning them by heart as a boy. From them grew a professional science of law. Praetors issued yearly edicts, and jurists wrote opinions on property, contracts and inheritance that judges took seriously.

Did you know? The only nearly complete classical textbook of Roman law, the Institutes of Gaius, survived because a medieval scribe washed it off its parchment and wrote letters of St Jerome over it; Barthold Niebuhr spotted the hidden text in Verona in 1816.

The Republic itself collapsed in civil wars, and in 27 BC Augustus became a monarch in all but name. The law outlived the system that made it. Between AD 529 and 534 the Byzantine emperor Justinian had his lawyers compile the Corpus Juris Civilis, including the Digest, a vast anthology of the jurists' opinions. A manuscript of the Digest resurfaced in Italy in the eleventh century, and the law school of Bologna, traditionally dated to 1088, grew up around its study.

From Bologna, Roman law flowed into the universities of Europe, then into the Napoleonic Code of 1804 and the German civil code, and from them into the legal systems of continental Europe, Latin America, Quebec, Louisiana and Japan. Whenever a court in Paris, Santiago or Tokyo weighs a contract or a will, it is still, in a sense, consulting the jurists of Rome.

Magna Carta

On 15 June 1215, in a meadow at Runnymede beside the Thames, King John of England agreed to a long list of demands from rebel barons. The charter was sealed, not signed, and it was only a few years later that it came to be called Magna Carta, "the Great Charter", to tell it apart from a smaller charter about the royal forests. It was a peace treaty, and it failed almost at once.

Most of its 63 clauses deal with the grievances of rich landowners: inheritance payments, the rights of widows, debts, fish weirs on the Thames. Two clauses became immortal. Clause 39 promised that "no free man" would be seized, imprisoned or outlawed "except by the lawful judgement of his peers or by the law of the land". Clause 40 added: "To no one will we sell, to no one will we deny or delay right or justice." In 1215, "free man" left out a large part of the population, the unfree peasants known as villeins.

Within ten weeks Pope Innocent III declared the charter null and void, and England slid into civil war. Yet when John died in 1216, the regents of the boy-king Henry III reissued a revised version in his name, and did so again in 1217 and 1225. In 1297 Edward I confirmed it, and that text entered the statute books. We know the 1215 text from four surviving originals, two in the British Library and one each at Lincoln and Salisbury cathedrals.

Did you know? The Lincoln copy of Magna Carta was on show at the New York World's Fair when war broke out in 1939, and spent part of the Second World War locked in the gold vault at Fort Knox.

Its real power came from later readers. In the 1620s the lawyer Sir Edward Coke wielded it against Charles I, and it fed the Petition of Right of 1628. American colonists cited it against Parliament, and its echo can be heard in the "due process of law" of the Fifth Amendment. When the United Nations adopted the Universal Declaration of Human Rights in 1948, Eleanor Roosevelt hoped it might become "the international Magna Carta for all men everywhere". Other medieval charters struck similar bargains, such as Hungary's Golden Bull of 1222, which allowed nobles to resist a king who broke it.

Popular memory credits Magna Carta with inventing trial by jury and democracy; it did neither. Today only three of its clauses remain in force in England and Wales, including the promise of justice without sale, denial or delay. That is plenty. A failed treaty became the most famous statement of a simple idea: the king is under the law.

Parliaments

A parliament, from the French parler, "to talk", is an assembly that speaks for a wider community and shares in making laws and raising money. Kings had always taken advice from great men, but a parliament is different: it meets regularly, it represents people who are not in the room, and in time it learns to say no.

Some of the oldest roots lie in the north. In Iceland, chieftains and free farmers gathered every summer from around 930 at Thingvellir for the Althing, an open-air assembly where a lawspeaker recited the law from a rock. In 1188 Alfonso IX of León summoned bishops, nobles and, crucially, representatives of the towns to the Cortes of León, whose decrees UNESCO recognised in 2013 as the oldest documentary evidence of the European parliamentary system.

England's version grew out of money. Kings needed taxes for wars, and barons and towns wanted something in return. In 1265 the rebel Simon de Montfort summoned not only lords but also knights from the shires and burgesses from the towns. Over the next century Parliament divided into Lords and Commons, and the principle hardened that new taxes needed its consent. In Poland the noble Sejm won the statute Nihil novi in 1505: nothing new without the consent of the assembly. From 1652 a single deputy could wreck a whole session with the liberum veto, a cautionary tale about consensus taken too far.

Parliaments spread with written constitutions. The Imperial Diet of Japan first met in 1890, and India's first general election in 1951 and 1952 gave a parliament to the world's largest democracy. Even the furniture matters. In the French revolutionary assembly of 1789, radicals sat on the president's left and conservatives on his right, which gave politics its "left" and "right". Westminster's facing benches encourage confrontation, and when the bombed House of Commons was rebuilt after 1941, Winston Churchill insisted it keep its old cramped oblong shape, arguing that "we shape our buildings and afterwards our buildings shape us".

Did you know? The rebuilt Commons chamber has far fewer seats than its 650 MPs, so on big occasions members cram the gangways and stand at the bar of the House.

Today almost every state has a parliament, including dictatorships, which value the appearance of consent. The real test is older than any building: whether the assembly can still refuse the ruler money, laws and, at the last, obedience.

Empires and How They Ruled

An empire is a state that rules many peoples and territories from a single centre, usually won by conquest. Taking land is the easy part. Holding it across deserts, mountains and languages, with messages moving no faster than a horse or a runner, is the real achievement, and every lasting empire had to solve the same problems: officials, roads, records and loyalty.

The Achaemenid Persians, from around 550 BC, set the pattern. They divided their realm into provinces under governors called satraps; Herodotus lists twenty of them. A Royal Road ran about 2,500 kilometres from Sardis to Susa, with staging posts where fresh horses waited, and Herodotus marvelled that neither snow nor rain nor heat nor gloom of night stopped the royal couriers. Darius I proclaimed his rule in three languages on the cliff of Behistun, and Persian kings generally left local gods, laws and customs alone, so long as the tribute arrived.

China's emperors bound their realm with paper and standards. The Qin, after 221 BC, standardised script, weights and coinage, and divided the land into commanderies and counties run by appointed officials rather than hereditary lords. The Han founded an imperial academy for Confucian learning, and from the seventh century civil service examinations chose officials by merit, in theory at least; they lasted until 1905. Rome took another route, turning conquered elites into citizens. In AD 212 the emperor Caracalla extended citizenship to almost every free inhabitant of the empire.

In the Andes the Inca ruled millions of people without writing as we usually define it. Their road network, the Qhapaq Ñan, carried relay runners called chasquis, and officials kept census and tribute accounts on khipu, cords of knotted string. Subjects paid tax in labour, the mit'a. In the thirteenth century the Mongols ran the yam, a relay system of horse stations, and issued metal tablets called paiza as passports for officials. Much later, Britain governed princely India and northern Nigeria through indirect rule, leaving princes and emirs in place under British supervision.

Did you know? Hundreds of Inca khipu survive in museums, and researchers can read their numbers, which are recorded in knots on a base-ten system, but whether some cords also recorded words or stories is still debated.

Every empire eventually fell, but its methods outlived it. Provinces, censuses, passports, postal relays and examinations for public servants are all imperial inventions that modern states quietly inherited.

Revolutions and Rights

A right is a claim that does not depend on a ruler's favour. For most of history people had privileges instead, granted to a town, a guild or a noble family and revocable by a king. The idea that every person holds certain rights simply by being human was argued by philosophers such as John Locke, but it took revolutions to write it into law.

The first steps were English. After the overthrow of James II, Parliament's Bill of Rights of 1689 barred the crown from raising taxes or keeping a standing army in peacetime without Parliament's consent, and forbade "cruel and unusual punishments". In 1776 the American colonies justified independence with the claim that "all men are created equal", endowed with "certain unalienable Rights", among them "Life, Liberty and the pursuit of Happiness". Their author, Thomas Jefferson, enslaved more than six hundred people over his lifetime, a contradiction the new nation would take a civil war to confront.

In Paris on 26 August 1789 the National Assembly adopted the Declaration of the Rights of Man and of the Citizen: "Men are born and remain free and equal in rights." Olympe de Gouges answered in 1791 with a Declaration of the Rights of Woman, and was guillotined in 1793. The most radical revolution of the age began that same year in the French colony of Saint-Domingue, where enslaved Africans rose up in 1791. Led by Toussaint Louverture and later Jean-Jacques Dessalines, they defeated French, Spanish and British forces, and on 1 January 1804 declared the independent state of Haiti, the first nation founded after a successful revolt of enslaved people.

Rights spread unevenly through the nineteenth century, with Latin American independence under Simón Bolívar and others, the abolition of slavery and new constitutions across Europe. After the horrors of the Second World War, the United Nations adopted the Universal Declaration of Human Rights on 10 December 1948. Its drafting committee, chaired by Eleanor Roosevelt, included the Chinese diplomat Peng Chun Chang, the Lebanese philosopher Charles Malik and the French jurist René Cassin, so its ideas were not merely Western.

Did you know? The Cyrus Cylinder of around 539 BC is often called the first charter of human rights, and a replica is displayed at UN headquarters, but historians read it as traditional Babylonian royal propaganda rather than a declaration of rights.

Declarations are promises, not guarantees, and history is full of rights proclaimed for some and denied to others. But once written, a promise can be quoted back at those who made it, and that is how most of the rights we now take for granted were won.

Votes for All

Voting is ancient; voting for everyone is astonishingly recent. Athenian citizens voted with raised hands and pottery sherds, Romans voted in blocks by tribe and century, and medieval churchmen elected popes and abbots. From 1356 the Golden Bull fixed seven prince-electors to choose the Holy Roman Emperor. In every case the voters were a narrow club, almost always male and usually wealthy.

Widening the franchise, the right to vote, was a long fight. In Britain the Great Reform Act of 1832 gave votes to more middle-class men and swept away "rotten boroughs" with hardly any voters. In 1838 the Chartists demanded a vote for every man and a secret ballot; they were dismissed in their day, yet most of their six points are now law. The secret ballot itself came from Australia: in 1856 the colonies of Victoria and South Australia introduced government-printed ballot papers marked in private, which is why Americans once called it the "Australian ballot". Britain followed in 1872.

Women's suffrage began at the edges of the map. In 1893 New Zealand became the first self-governing country to give women the vote in national elections, after petitions organised by Kate Sheppard. In 1906 Finland gave women both the vote and the right to stand, and in 1907 nineteen women entered its parliament. In Britain the suffragists and the militant suffragettes of Emmeline Pankhurst campaigned for decades; women over thirty who met property qualifications won the vote in 1918, and equal terms with men followed in 1928. The United States ratified the Nineteenth Amendment in 1920.

Race and class closed doors too. The Fifteenth Amendment of 1870 promised Black American men the vote, but poll taxes, literacy tests and violence stripped it away across the South until the Voting Rights Act of 1965, passed after the marches from Selma. French women won the vote in 1944 and first used it in 1945. India wrote universal adult suffrage into its 1950 constitution, and its first general election, in 1951 and 1952, was the largest the world had yet seen. In April 1994 South Africans of every race queued for hours to vote together for the first time, and elected Nelson Mandela.

Did you know? Switzerland gave women the vote in federal elections only in 1971, and the canton of Appenzell Innerrhoden held out on local matters until the Federal Supreme Court forced it to change in 1990.

Arguments continue about voting ages, prisoners, residents and compulsory voting, used in Australia since 1924. But the direction of history is clear: each generation has found that some group once thought unfit to vote was nothing of the kind.

Courts, Juries and Police

Every society needs a way to settle disputes and punish wrongs without a blood feud. Over time three institutions took on the job: courts, which decide what happened and what the law requires; juries, which put ordinary people in the judgement seat; and police, a surprisingly modern idea, who keep order and catch suspects on the state's behalf.

Courts left early paperwork. Mesopotamian clay tablets record lawsuits over land, loans and inheritance, with witnesses and oaths sworn before the gods. In Egypt the tomb-builders' village of Deir el-Medina had its own local court, the kenbet, whose rulings on stolen tools and unpaid debts survive on flakes of limestone, and papyri from the reign of Ramesses IX, around 1110 BC, record the interrogation of tomb robbers. In the Islamic world the qadi judged by sharia, while the muhtasib checked markets for false weights. In imperial China the county magistrate was detective, prosecutor and judge rolled into one; Bao Zheng, an eleventh-century official, became the legendary incorruptible Judge Bao.

Juries have two ancestors. Athens used huge citizen juries, while in England Henry II's Assize of Clarendon of 1166 required groups of local men to report suspected criminals to the royal judges. When the Fourth Lateran Council of 1215 forbade priests to bless trials by ordeal, English courts turned to juries to decide guilt instead. Over the centuries the jury became a check on the state as well as a tool of it.

Did you know? In 1670 a London jury refused to convict the Quaker William Penn and was fined and jailed for it, but its foreman, Edward Bushel, won his case, establishing that jurors cannot be punished for their verdict.

Police came last. Rome had the vigiles, night watchmen and firefighters created by Augustus. Most later European towns relied on watchmen and part-time constables, until Louis XIV appointed a lieutenant general of police for Paris in 1667. In London the magistrate and novelist Henry Fielding organised the Bow Street Runners in 1749, and in 1829 the Home Secretary Robert Peel founded the Metropolitan Police, uniformed, unarmed and deliberately unlike an army; Londoners nicknamed its officers "peelers" and "bobbies". Japan's neighbourhood police boxes, the kōban, show another model: policing by presence.

Today most countries combine professional judges and police forces, and some keep juries, while the International Criminal Court, founded in 2002, tries crimes that no single state will. The basic promise is unchanged since the first clay tablet: a wrong will be judged by rules, not by revenge.

Ancient Healers

Long before anyone wrote a prescription, people were treating wounds, setting bones and cutting into skulls. The oldest evidence of healing is not a text but a body: skulls from Neolithic Europe, Peru and North Africa carry neat round holes made by trepanation, and many show smooth regrowth of bone around the edges. The patients lived, sometimes for years. Why the holes were made, whether for head injuries, headaches or spirits, historians and archaeologists still debate.

Writing turned private skill into shared knowledge. In Egypt the Edwin Smith Papyrus, copied around 1600 BC from an older original, works through 48 cases of injury from head to spine, each with an examination, a verdict and a treatment. Its calm, practical tone is startling: some wounds are marked as ones to treat, others as "an ailment not to be treated". The Ebers Papyrus of around 1550 BC gathers hundreds of remedies, from honey on wounds to charms against demons. In Mesopotamia, clay tablets describe two kinds of healer, the asû who used drugs and bandages and the āšipu who dealt with omens and spirits, and the laws of Hammurabi set penalties for surgeons whose patients came to harm.

Further east, other traditions grew up with their own logic. The Sanskrit Sushruta Samhita, whose dates historians debate, describes more than a hundred surgical instruments and an operation to rebuild a lost nose with a flap of living skin, a technique later called the Indian method. In China the Yellow Emperor's Inner Classic, compiled around the 2nd or 1st century BC, explains health as a balance of yin and yang and the flow of qi through channels, the framework behind acupuncture.

Did you know? Bone regrowth around trepanation holes shows that many Neolithic patients survived having their skulls opened, some more than once.

In Greece, the writings gathered under the name of Hippocrates of Kos, who lived around 460 to 370 BC, made a quiet revolution: they treated epilepsy, long called "the sacred disease", as having a natural cause like any other. Physicians were urged to observe, to record the course of an illness and above all to avoid doing harm. Alongside them, the sick still slept in the temples of Asclepius at Epidaurus, hoping for a healing dream; ancient patients saw no contradiction in trying both.

None of these healers knew about germs, and many of their cures did nothing at all. What they left was a habit: look closely, write it down and pass it on. Every later chapter of medicine stands on that ledge.

The Four Humours

For roughly two thousand years, a doctor examining you in Athens, Baghdad, Paris or Boston would have seen your body as a vessel of four fluids. This was the theory of the four humours: blood, phlegm, yellow bile and black bile. Health meant keeping them in balance; illness meant one had grown too strong or too weak. It sounds quaint now, but it was a coherent system that explained almost everything, which is exactly why it lasted so long.

The earliest clear statement is the Hippocratic treatise On the Nature of Man, written around 400 BC and often credited to Hippocrates's son-in-law Polybus. It tied each humour to the qualities hot, cold, wet and dry, and to the seasons: blood to spring, yellow bile to summer, black bile to autumn and phlegm to winter. Later writers matched them to the four elements of air, fire, earth and water. The theory was not built from dissection but from watching what the body produced, from nosebleeds to vomit, and from the plain observation that colds come in winter.

The great systematiser was Galen of Pergamon, born in AD 129, physician to gladiators and then to emperors in Rome. Galen wrote so much, and so confidently, that his version became the standard. Translated into Arabic in Baghdad in the 9th century, it was refined by scholars such as Ibn Sina, whose Canon of Medicine, completed around 1025, was still being taught in European universities six centuries later. Similar ideas of balance ran through other systems too: Ayurveda in India speaks of three doshas, and Chinese medicine of yin and yang.

Did you know? The word melancholy comes from the Greek melaina kholē, "black bile", the humour once blamed for gloom.

If illness was excess, treatment was removal. Physicians and barber-surgeons bled patients, purged them, made them vomit and prescribed cooling or warming foods. Bloodletting was used for fevers, headaches and much else; in 1799 George Washington was bled heavily during his final illness. Doubts grew slowly. William Harvey's 1628 proof that blood circulates undermined the old picture of the body, and in the 1830s the French doctor Pierre Louis counted outcomes and found bleeding did little good for pneumonia. Germ theory finished the job.

Yet the humours never quite left. We still call people sanguine, phlegmatic or bilious, and we still talk about being in a good humour. The theory was wrong, but it lives on in the way we describe our moods.

Plague

Plague is caused by a bacterium, Yersinia pestis, that lives in rodents and passes to people mainly through the bites of infected fleas. In its bubonic form it swells the lymph glands into painful buboes; in its pneumonic form it spreads from person to person through the air. It has struck in three great waves, and its name has become a byword for catastrophe.

For centuries historians argued about what the great medieval mortality really was. The answer came from teeth. Dental pulp can preserve the DNA of blood-borne bacteria, and in 2011 researchers recovered the genome of Y. pestis from victims buried in the East Smithfield plague pit in London in 1348 and 1349. Since then, plague DNA has turned up in Bronze Age skeletons around five thousand years old, and gravestones near Lake Issyk-Kul in Kyrgyzstan, dated 1338 and 1339 and recording deaths from "pestilence", have yielded the strain that seems to stand at the root of the medieval outbreak.

The first recorded pandemic, the Plague of Justinian, reached Constantinople in 542, and recurring outbreaks around the Mediterranean followed for two centuries. The second began with the Black Death, which arrived in Sicily in 1347 and swept across Europe, the Middle East and North Africa by 1353. Estimates vary, but it probably killed between a third and a half of Europe's people. Labour grew scarce, wages rose in many places, and in the Rhineland and elsewhere Jewish communities were massacred by neighbours seeking someone to blame.

Without knowing the cause, cities still learned to defend themselves. In 1377 the port of Ragusa, now Dubrovnik, ordered arrivals from infected places to wait thirty days before entering. Venice and others stretched the wait to forty days and built isolation hospitals, the lazzaretti. In 1665 the English village of Eyam, struck by plague from a parcel of cloth from London, chose to seal itself off to protect its neighbours.

Did you know? The word quarantine comes from the Venetian quaranta giorni, "forty days", the length of isolation imposed on ships.

The third pandemic spread from Yunnan in China and reached Hong Kong in 1894, where Alexandre Yersin identified the bacterium that now bears his name; Kitasato Shibasaburō studied it there at the same time. In 1898 Paul-Louis Simond showed that fleas carried it from rats. Plague has never vanished: it still circulates among wild rodents on several continents, and Madagascar suffered a serious outbreak in 2017. The difference is that antibiotics now cure it if they are given early. The disease that emptied cities has become, for those within reach of a doctor, a treatable infection.

Anatomy and Dissection

Anatomy is the map of the body, and for most of history it was drawn from guesswork. Opening the dead was taboo in many cultures, so physicians reasoned from animals, from wounds and from philosophy. The few moments when people were allowed to look inside human bodies mark some of the biggest leaps in medicine.

The first came in Alexandria in the 3rd century BC. There Herophilus and Erasistratus dissected human bodies, traced the nerves to the brain and described the valves of the heart. Ancient writers later accused them of cutting open living criminals; historians debate whether this was true. Their own books are lost, and we know their work mainly through later authors. Galen, four centuries later, dissected pigs and Barbary apes instead, and some of his errors, such as a network of vessels at the base of the brain that humans do not have, were taught for well over a thousand years.

Human dissection returned in medieval Italy. In Bologna around 1315, Mondino de' Liuzzi performed public dissections and wrote a short manual, the Anathomia, that students used for two centuries. Around 1510 Leonardo da Vinci made astonishing anatomical drawings, though they stayed unpublished for centuries. Elsewhere, Ibn al-Nafis in 13th-century Cairo described blood passing through the lungs, correcting Galen without the benefit of a scalpel. The decisive book was Andreas Vesalius's De humani corporis fabrica, printed in Basel in 1543, whose superb woodcuts showed the body as it actually is and openly corrected Galen.

Anatomy became a public spectacle. Padua built a permanent anatomy theatre in 1595, a steep wooden funnel of tiers where students stood to watch the professor below, and it survives today. Rembrandt painted The Anatomy Lesson of Dr Nicolaes Tulp in Amsterdam in 1632. In Japan, Sugita Genpaku and his colleagues watched the dissection of an executed criminal in 1771, compared it with a Dutch textbook and found the Dutch pictures accurate, which led to their translation, Kaitai Shinsho, in 1774.

Did you know? Edinburgh's William Burke gave English a verb: to burke, meaning to smother, after he and William Hare murdered people in 1828 to sell their bodies to an anatomist.

That scandal shows the dark side: demand for bodies far outran supply, and grave robbers filled the gap. Britain's Anatomy Act of 1832 allowed unclaimed bodies from workhouses and hospitals to be used instead, which shifted the burden onto the poor. Today most anatomy depends on people who choose to donate their bodies, alongside scans and digital models built from sliced cadavers. The map is now detailed down to the cell, and it was drawn by people who dared to look.

Vaccination

A vaccine teaches the immune system to recognise a disease before the disease arrives. That idea, now so ordinary that most of us have forgotten our childhood jabs, began with a deliberate and dangerous gamble against smallpox, one of the deadliest diseases in human history.

Long before anyone understood immunity, people noticed that survivors of smallpox never caught it again. From that observation grew variolation: giving a healthy person a small dose of real smallpox, usually through a scratch or, in China, by blowing powdered scabs into the nose. Chinese texts describe the method by the 16th century, and it was also practised in India, Africa and the Ottoman Empire. In 1721 Lady Mary Wortley Montagu, who had seen it in Constantinople, had her daughter variolated in London. That same year in Boston, the minister Cotton Mather promoted it after learning of it from Onesimus, an enslaved West African man who had been inoculated as a child. Variolation worked, but it could kill, and the patient could spread smallpox to others.

The safer step came from the English countryside, where milkmaids who had caught mild cowpox were said to be spared. On 14 May 1796 Edward Jenner took matter from a cowpox sore on the hand of the milkmaid Sarah Nelmes and scratched it into the arm of eight-year-old James Phipps. Weeks later he exposed the boy to smallpox; Phipps did not fall ill. Jenner was not the first to try cowpox, but he tested it, published his results in 1798 and promoted it tirelessly.

Did you know? The word vaccine comes from the Latin vacca, "cow", a nod to the cowpox behind Jenner's method.

Louis Pasteur widened the principle by weakening germs in the laboratory, and in 1885 he gave a rabies vaccine to nine-year-old Joseph Meister, who had been bitten by a rabid dog. The 20th century followed with vaccines against diphtheria, tetanus, whooping cough and measles, and Jonas Salk's polio vaccine was declared safe and effective in 1955. A worldwide campaign led by the World Health Organization tracked smallpox down village by village; the last natural case was in Somalia in 1977, and the disease was declared eradicated in 1980.

The newest step came in 2020, when vaccines using messenger RNA, built on decades of quiet research, were developed against Covid-19 in under a year. The method has changed from scabs to genetic code, but the principle Jenner tested on a boy in Gloucestershire is the same: a small, safe lesson now spares the body a deadly one later.

Germ Theory

For most of history, epidemics were blamed on miasma: bad air rising from rotting matter, swamps and filth. The word malaria itself means "bad air" in Italian. The idea was not foolish, since stinking places often were unhealthy, but it pointed people at smells instead of the true culprits, living organisms far too small to see. Germ theory, the idea that specific microbes cause specific diseases, took about three centuries to win.

In 1546 the Italian physician Girolamo Fracastoro suggested that contagion spread by tiny "seeds", but nobody could see them. In the 1670s the Dutch draper Antoni van Leeuwenhoek, grinding his own tiny lenses, became the first to describe bacteria, which he called "animalcules", in scrapings from his teeth. No one connected them to disease for a long time.

The evidence came first from counting. In Vienna in 1847, Ignaz Semmelweis noticed that far more mothers died of childbed fever on the ward run by doctors, who came straight from dissections, than on the midwives' ward. When he made staff wash in chlorinated lime, deaths fell sharply. Many colleagues rejected him. In London in 1854, John Snow mapped the deaths in a cholera outbreak in Soho and found them clustered around one water pump on Broad Street. Nearby, a workhouse with its own well and a brewery whose workers drank beer escaped almost untouched. Snow persuaded the local board to remove the pump's handle. That same year, unknown to him, Filippo Pacini in Florence described the cholera bacterium under the microscope.

Did you know? By the time the Broad Street pump handle was removed, the outbreak was already declining, as Snow himself acknowledged.

The proof arrived in the laboratory. Around 1860 Louis Pasteur boiled broth in swan-necked flasks that let in air but trapped dust; the broth stayed clear, showing that microbes came from other microbes, not from spontaneous generation. In Germany, Robert Koch identified the bacterium of anthrax in 1876, of tuberculosis in 1882 and of cholera in 1884, and set out a set of tests, now called Koch's postulates, for linking one germ to one disease.

Germ theory changed daily life as much as medicine. It gave us antiseptic surgery, pasteurised milk, filtered water, handwashing campaigns and, eventually, antibiotics and vaccines aimed at named enemies. The old fear of bad air was replaced by something more useful: knowing exactly what to fight.

Anaesthesia and Surgery

Before the 1840s, the best surgeon was a fast one. With no way to stop pain, operations were limited to what a conscious, struggling patient could survive: amputations, the removal of bladder stones, the lancing of abscesses. Assistants held the patient down, and a skilled surgeon could take off a leg in a few minutes. Opening the abdomen or the chest was almost unthinkable. Two discoveries in the 19th century, anaesthesia and antisepsis, changed that completely.

Pain relief was not new. Opium, alcohol and herbal mixtures had been used for millennia, with limited and unreliable effect. The first known operation under full general anaesthesia took place in Japan in 1804, when Hanaoka Seishū removed a breast tumour from a woman put to sleep with tsūsensan, a herbal drink he had developed over many years. Because Japan was largely closed to the outside world, his work was little known abroad.

In the West, the breakthrough came with gases. Humphry Davy had suggested in 1800 that nitrous oxide, laughing gas, might be used in surgery, but nobody followed it up. The American doctor Crawford Long used ether in Georgia in 1842 but did not publish until later. On 16 October 1846, at Massachusetts General Hospital in Boston, the dentist William Morton gave ether to a patient while a tumour was removed from his neck, and the news spread across the Atlantic within weeks. In 1847 James Young Simpson in Edinburgh introduced chloroform, which was easier to use.

Did you know? Queen Victoria was given chloroform by Dr John Snow in 1853 during the birth of Prince Leopold, which helped make it respectable.

Anaesthesia let surgeons work slowly, but patients still died afterwards from infected wounds. In Glasgow, inspired by Pasteur's work on germs, Joseph Lister began in 1865 to treat wounds and instruments with carbolic acid, and published his results in 1867. Infection rates on his wards fell. Over the following decades antisepsis, killing germs, gave way to asepsis, keeping them out altogether: steam-sterilised instruments, gowns, masks and, from around 1890 at Johns Hopkins, rubber gloves introduced by the surgeon William Halsted.

Together these changes made modern surgery possible: caesarean sections that mothers survived, operations on the bowel and the brain, and eventually open-heart surgery and transplants. The operating theatre, once a place of screams and speed, became one of quiet, gloved and patient work.

Hospitals and Nursing

A hospital is a simple idea with a complicated history: a building where the sick are cared for by people trained to do it. For most of history, people were nursed at home by their families. The first institutions grew up around religion, war and charity, and only in the last two centuries did they become places where most people expected to get better.

The temples of Asclepius in ancient Greece took in pilgrims, but they were shrines more than wards. The Romans built proper military hospitals, the valetudinaria, inside their forts; the foundations of one, with small rooms around a courtyard, have been excavated at Inchtuthil in Scotland. Christian charity founded hospices for the poor, pilgrims and the sick, such as the Hôtel-Dieu in Paris, traditionally dated to the 7th century, and St Bartholomew's in London, founded in 1123.

Some of the most advanced hospitals of the Middle Ages were in the Islamic world. The bimaristans of Baghdad, Damascus and Cairo had separate wards for fevers, eye diseases and mental illness, pharmacies, libraries and teaching for young physicians. The al-Mansuri hospital in Cairo, opened in 1284, treated patients regardless of wealth or religion. In Europe, nursing stayed largely in the hands of religious orders, while in many lay hospitals it was low-paid and poorly regarded work.

That changed with the Crimean War. In 1854 Florence Nightingale took a party of nurses to the British army hospital at Scutari, near Constantinople, where soldiers were dying in great numbers of disease rather than wounds. She brought order, clean linen, food and records. The Jamaican-born nurse Mary Seacole, turned down for official service, travelled to the Crimea at her own expense and ran the British Hotel near Balaclava, where she fed and nursed soldiers. Back in London, Nightingale used statistics to campaign for reform, wrote Notes on Nursing in 1859 and opened a training school at St Thomas' Hospital in 1860.

Did you know? In 1858 Florence Nightingale became the first woman elected a Fellow of the Royal Statistical Society, thanks to her pioneering charts.

Her ideas shaped hospitals for a century. The pavilion ward, long and narrow with tall windows on both sides, let fresh air and light reach every bed and let a single nurse see every patient. Trained nursing became a respected profession around the world. In 1948 Britain's National Health Service made hospital care free at the point of use, and many countries built their own systems. The modern hospital, with its specialist units and intensive care, still rests on Nightingale's simple demand: a clean bed, fresh air and someone watching.

Antibiotics

An antibiotic is a drug that kills bacteria or stops them from multiplying, while leaving the patient largely unharmed. Before them, a scratched knee, a sore throat or childbirth could lead to a fatal infection, and doctors had little to offer beyond rest and hope. Within about two decades in the 20th century, that changed.

The search began with chemistry. In 1910 Paul Ehrlich's team in Frankfurt launched Salvarsan, an arsenic compound that treated syphilis, the first "magic bullet" aimed at a single microbe. In 1935 Gerhard Domagk in Germany reported that a red dye, Prontosil, cured streptococcal infections; it opened the age of the sulfa drugs, which saved many lives before penicillin was widely available.

The most famous discovery was an accident. In September 1928 Alexander Fleming, returning from holiday to his laboratory at St Mary's Hospital in London, noticed that a mould had contaminated a dish of Staphylococcus bacteria, and that around it the bacteria had died, leaving a clear ring. The mould was Penicillium, and Fleming called its active substance penicillin. He published in 1929, but he could not purify it in useful amounts, and the work largely stalled.

It was revived in Oxford, where Howard Florey, Ernst Chain and Norman Heatley found ways to extract and purify penicillin. In 1940 they showed it protected infected mice. In 1941 their first patient, the police constable Albert Alexander, improved dramatically but died when the tiny supply ran out. Mass production moved to the United States, where a mould found on a cantaloupe in a market in Peoria, Illinois, proved a far better producer. By the Normandy landings in 1944, there was enough penicillin for Allied troops. Fleming, Florey and Chain shared the Nobel Prize in 1945, and in 1943 Selman Waksman's laboratory found streptomycin, the first effective drug against tuberculosis.

Did you know? Bones from Sudanese Nubia, dated to around AD 350 to 550, contain the antibiotic tetracycline, probably from beer brewed with grain hosting Streptomyces bacteria.

From the start, there was a warning. In his Nobel lecture Fleming cautioned that underdosing could breed resistant bacteria, and he was right. Overuse in medicine and farming has bred resistance, including strains such as MRSA that shrug off many drugs, while few new classes of antibiotic have been found in recent decades. Antibiotics turned deadly infections into minor ones within a single lifetime. Keeping them working now depends on using them with care.

Public Health: Sewers, Water and Clean Air

Some of the greatest lifesavers in history were not doctors but engineers. Public health is the work of keeping whole populations well: clean water in, waste out, air fit to breathe. It saves more lives than any single cure, and because it works out of sight, it is easy to forget.

The oldest drains are more than four thousand years old. At Mohenjo-daro in the Indus Valley, around 2500 BC, many houses had bathing platforms connected to covered brick drains running along the streets. Rome brought water from the hills by aqueduct, starting with the Aqua Appia in 312 BC, and its great sewer, the Cloaca Maxima, still drains part of the city. After Rome, many European towns let waste run in open channels into rivers that also supplied drinking water, with predictable results.

Industrial cities made the problem deadly. Cholera struck Britain repeatedly from 1832. In 1842 the reformer Edwin Chadwick published a report linking disease to filthy living conditions, and the Public Health Act of 1848 created boards of health. Then came the hot summer of 1858, the Great Stink, when the sewage-choked Thames smelled so foul that the curtains of the Houses of Parliament were soaked in chloride of lime. Parliament quickly approved the engineer Joseph Bazalgette's plan: intercepting sewers running parallel to the river to carry waste east, away from the city, to outfalls at Beckton and Crossness. Much of it was hidden inside the new Victoria Embankment, which also carried a road and an underground railway.

Did you know? The Great Stink of 1858 pushed Parliament to pass the law funding London's new sewers that same summer, after years of delay.

Clean water followed. Filtering through sand beds spread in the 19th century, and from 1908 Jersey City in the United States began continuous chlorination of its public supply, a method that spread worldwide and sharply reduced typhoid. Clean air came later still. In December 1952 a thick smog, trapped over London for five days, killed thousands of people. The response was the Clean Air Act of 1956, which created smoke-free zones and moved homes away from burning coal; the United States passed its own Clean Air Act in 1970, and leaded petrol was phased out across the world over the following decades.

Today more than half the world's people have safely managed drinking water, but billions still lack it, and air pollution remains a major cause of illness. The tunnels, pipes and treatment works beneath our streets rarely make the news. Their quiet success is measured in the illnesses that never happen.

The Farming Revolution

For most of the human story, people ate what they could gather, hunt or catch. Then, starting around 11,500 years ago, some communities began to sow seed, keep animals and stay put. The archaeologist V. Gordon Childe called this the Neolithic Revolution in the 1930s, though it was less a sudden revolt than a slow drift lasting thousands of years, and it happened not once but in several places independently.

The earliest clear case is the Fertile Crescent, the arc of hills from the Levant to the Zagros Mountains. Here people turned wild wheat, barley, lentils and peas into crops, and wild sheep, goats and cattle into herds. How do we know? Charred seeds in ancient hearths tell the tale. Wild wheat shatters, scattering its grains to the wind; domesticated wheat keeps them on the stalk until a farmer harvests it. Under the microscope the broken base of each spikelet shows which kind it was, and radiocarbon dates those seeds to the millennium after 9500 BC. Animal bones shift too, towards smaller beasts and herds weighted with young males culled for meat.

Elsewhere, farming grew from entirely different plants. In China, rice was tamed along the Yangtze and millet along the Yellow River by around 7000 BC. In Mexico, people slowly reshaped a scraggly wild grass called teosinte into maize, with squash and beans alongside it. In the Andes, potatoes, quinoa, llamas and guinea pigs became staples. Highland New Guinea cultivated taro and bananas, Africa's Sahel grew sorghum and pearl millet, and eastern North America domesticated sunflowers and goosefoot.

Did you know? A wild teosinte ear is barely the length of a thumb, holding about a dozen kernels wrapped in stone-hard cases.

Farming was not an obvious improvement. Skeletons of early farmers are often shorter than those of their foraging ancestors, with more tooth decay, more anaemia and more signs of hard labour. Crowded villages, living beside animals, bred new diseases. Göbekli Tepe in Turkey, a ring of carved stone pillars raised around 9500 BC apparently by hunter-gatherers, has led some historians to ask whether feasting and ritual helped draw people towards cultivation. The debate is very much alive.

Yet farming won, because it fed more people per acre. Surpluses could be stored, taxed and traded, which made possible villages, then towns, specialists, kings and scribes. Nearly every calorie eaten today comes from crops and animals first domesticated in those few early centres, and more than half of them come from just three grasses: rice, wheat and maize. We still live in the world those first farmers sowed.

Bread and Grain

Grain is a stubborn food. A raw wheat kernel is hard, dry and nearly indigestible, so people have spent millennia finding ways to crack it, grind it, soak it and heat it. Bread, porridge, noodles and tortillas are all answers to the same problem, and for most of history they were simply what most people ate, most of the time.

The oldest bread yet found is older than farming. In 2018 archaeologists reported charred crumbs from fireplaces at Shubayqa 1 in north-east Jordan, left by Natufian hunter-gatherers about 14,400 years ago. Under a scanning electron microscope the crumbs showed the bubbles and crushed husks of a flatbread made from wild cereals and tubers. Some researchers suggest that the effort of baking such a treat may even have encouraged people to cultivate cereals.

The tools tell the story of the labour. A saddle quern, a flat stone rubbed with a smaller one, could turn grain into flour, at the cost of hours each day; skeletons of women in early farming villages show worn knees, toes and backs from kneeling at the stone. Egyptians baked in moulds and ovens, and excavations near the Giza pyramids uncovered bakeries that fed the builders. Romans gave bread political weight: from 123 BC Gaius Gracchus subsidised grain for citizens, and later the city's poor received it free. At Pompeii, the eruption of AD 79 sealed a bakery with its donkey-turned millstones and dozens of carbonised loaves, each scored into eight wedges for sharing.

Bread was never the only answer. In Mesoamerica, maize was soaked in lime water, a process called nixtamalisation, which unlocks its nutrients and makes the dough for tortillas. In China, wheat became noodles and steamed buns, while rice was boiled whole. In Ethiopia, the tiny grain teff is fermented into spongy injera. The price of grain moved history: bread riots ran through the French Revolution, and Britain's fight over the protective Corn Laws ended with their repeal in 1846.

Did you know? The English word lord comes from Old English hlāfweard, "loaf-keeper", and lady from hlǣfdīge, "loaf-kneader".

Industry transformed the loaf. Steam-powered roller mills in the 1800s made cheap white flour, and in 1961 British researchers at Chorleywood devised a method that uses intense mixing to cut fermentation time drastically; most British bread is still made that way. Today wheat, rice and maize provide the bulk of humanity's food energy. Every loaf on a supermarket shelf is the descendant of a crumb in a Jordanian hearth.

The Plough and the Field

A seed needs loosened soil, and for the first farmers that meant digging sticks and hoes. The plough changed the scale of things. Pulled by animals, it let one family turn far more land than muscle alone could manage, and it left marks that archaeologists can still read.

The earliest plough was the ard, a pointed wooden spike that scratched a furrow without turning the soil over. Because it only scratched, farmers often crossed each field twice at right angles. That criss-cross pattern survives in a few lucky places: under the South Street long barrow in Wiltshire, ard marks of around 3500 BC were sealed beneath the mound and preserved, and at Kalibangan in India a ploughed field of the early Harappan period shows furrows in a grid. Mesopotamian seals and Egyptian tomb paintings show oxen pulling ards, a ploughman behind, and sometimes a sower dropping seed through a funnel.

The next leap was the mouldboard, a curved board that lifts and flips the soil, burying weeds and opening heavy ground. Chinese farmers were using cast-iron mouldboards by the Han dynasty, more than two thousand years ago. In northern Europe, the heavy wheeled plough spread in the early Middle Ages. It needed a team of up to eight oxen, too many for one household, so neighbours pooled animals and ploughed long strips in great shared open fields. Villages rotated crops between fields, often wheat, then beans or barley, then a fallow year. Turning the cumbersome team at each end pushed soil into the middle of every strip, building the corrugated ridge and furrow still visible in English Midlands pastures.

Did you know? Ridge and furrow survives best under grass, so the earthworks of medieval ploughing are often clearest in fields that have not been ploughed for centuries.

Later centuries brought lighter, stronger designs. The triangular Rotherham plough of the 1730s needed fewer animals, and in 1837 the American blacksmith John Deere built a steel plough that could slice the sticky prairie sod. Then came engines: Henry Ford's mass-produced Fordson tractor appeared in 1917. Deep ploughing of the Great Plains followed by drought in the 1930s helped create the Dust Bowl, when topsoil blew away in black clouds.

Today many farmers practise no-till farming, sowing directly into the previous crop's stubble to protect the soil. The plough's shape is everywhere around us, though: in field boundaries, village layouts and the old word acre, once roughly the land a team could plough in a day. The landscape is a manuscript written with a blade.

Salt, Sugar and Spice

Salt keeps us alive, sugar delights us and spices make food interesting. None of the three is strictly a meal, yet each has been worth fighting, taxing and travelling for.

Salt is essential for the body and, before refrigeration, for preserving meat and fish. At Hallstatt in Austria, prehistoric miners dug deep into a mountain of rock salt, and the salt itself preserved their tools, clothing and even a wooden staircase that tree rings date to 1344 BC. Because everyone needs it, salt is easy to tax. China's Han emperors made salt and iron state monopolies in 117 BC, provoking a famous court debate recorded as the Discourses on Salt and Iron. France's hated salt tax, the gabelle, fed the anger behind the Revolution. In 1930 Mohandas Gandhi walked for 24 days to the sea at Dandi and picked up a lump of natural salt, defying Britain's salt laws in front of the world's press. The popular claim that Roman soldiers were paid in salt, giving us the word salary, is less certain: the word does come from sal, but how remains debated.

Sugar began as a grass. Sugar cane was domesticated in New Guinea perhaps 10,000 years ago, and Indian cooks learned to boil its juice into crystals; the Sanskrit word khanda gave us candy. Arab growers spread cane around the Mediterranean, then Europeans carried it to Madeira, Brazil and the Caribbean. There, sugar plantations worked by enslaved Africans became the engine of the Atlantic slave trade. In 1747 the German chemist Andreas Marggraf showed that beet contained the same sugar, and the first beet sugar factory opened in Silesia in 1801. Napoleon, cut off from Caribbean cane by British blockade, backed beet with enthusiasm.

Did you know? When the Egyptian pharaoh Ramesses II was mummified in 1213 BC, embalmers placed black peppercorns in his nostrils.

Spices such as pepper, cinnamon, cloves and nutmeg grew only in a few tropical places, mostly in South and Southeast Asia, which made them light, valuable and perfect for long-distance trade. Roman cookbooks call for pepper in almost every recipe, and medieval European nobles flaunted spiced dishes as a sign of wealth. The hunt for their source drove ocean voyages and colonial wars, a story told in its own chapter.

Today salt is cheap, sugar is everywhere and pepper sits on every café table. Health advice now asks us to eat less of the first two. Yet the mines, tax offices, plantations and trade routes they created shaped the modern world as surely as any empire. History, it turns out, has a very particular taste.

The Columbian Exchange

Before 1492 there were no tomatoes in Italy, no chillies in India, no potatoes in Ireland and no horses on the American plains. Within a century of Christopher Columbus crossing the Atlantic, all of that had changed. The historian Alfred Crosby named this vast swap of plants, animals and microbes the Columbian Exchange in a 1972 book, and it remains one of the biggest ecological upheavals in human history.

From the Americas came maize, potatoes, sweet potatoes, tomatoes, chillies, beans, squash, peanuts, cassava, cacao, vanilla and tobacco. These crops travelled astonishingly fast. Portuguese traders had carried chillies to India and Southeast Asia by the sixteenth century, and cooks there made them their own. Cassava and maize became staples across much of Africa. The sweet potato reached China in the 1590s, where it helped farmers grow food on hillsides too poor for rice. The potato eventually fed the growing populations of northern Europe, and in Ireland so completely that its failure in the 1840s brought catastrophe. Even Italy's tomato sauce is a newcomer: one of the first printed recipes appeared in Naples in 1692.

Westward went wheat, rice, sugar cane, coffee, bananas and citrus, along with horses, cattle, pigs, sheep and chickens. Columbus's second voyage in 1493 already carried livestock and cane. Pigs ran wild and multiplied, cattle filled the pampas, and sugar planted in Brazil and the Caribbean drew millions of enslaved Africans across the ocean. Horses transformed the lives of Plains peoples such as the Comanche and Lakota, who became some of the finest riders in the world.

Did you know? Horses first evolved in North America, died out there over 10,000 years ago, and returned only on Spanish ships.

The most devastating cargo was invisible. Smallpox, measles and influenza had never circulated in the Americas, and Indigenous peoples had no resistance. Epidemics often ran ahead of the conquerors themselves, emptying towns before Europeans arrived. Historians debate the size of the pre-contact population and so the scale of loss, but most agree that the toll ran into millions and that some regions lost the great majority of their people, one of the deadliest demographic disasters ever recorded.

How do historians trace all this? Through ships' manifests, botanical drawings, recipes, Spanish colonial records, Indigenous codices, and archaeology of pollen, seeds and animal bones that suddenly change in a single layer. Look at any dinner plate today, from Thai curry to Irish stew, and you are looking at the Exchange still in progress. The world's menu was rewritten in a single generation.

Famine and Feast

Every society has lived between two poles: the feast, when food is shared lavishly to celebrate, impress or bind people together, and the famine, when food fails and people die. Both leave traces, and both reveal how a society is organised.

Feasting is ancient. At Durrington Walls, the great timber circle near Stonehenge, archaeologists have found thousands of pig bones from around 2500 BC. The animals' teeth show that most were slaughtered in midwinter, and chemical isotopes in their bones suggest some were raised as far away as Scotland, walked or carried hundreds of miles to be eaten together. In 879 BC the Assyrian king Ashurnasirpal II celebrated his new palace at Nimrud with a ten-day banquet; an inscribed stone, the Banquet Stele, lists the oxen, sheep, bread and beer and claims 69,574 guests. On the Pacific coast of North America, peoples such as the Kwakwaka'wakw held potlatch feasts at which chiefs gave away food and goods to affirm status. Canada banned the potlatch in 1884, and the ban was not lifted until 1951.

Famine leaves different evidence. Skeletons record childhood hunger as lines in teeth and bones. Tree rings and ice cores reveal the cold, wet summers and volcanic eruptions that ruined harvests. Chroniclers describe the Great Famine of 1315 to 1317, when relentless rain rotted crops across northern Europe. In dry years, so-called hunger stones emerge from the river Elbe, carved by earlier generations to mark drought.

Did you know? One hunger stone in the Elbe at Děčín, in the Czech Republic, carries the carved warning "Wenn du mich siehst, dann weine": "If you see me, weep".

Modern famines show that hunger is rarely just about a lack of food. During Ireland's Great Famine of 1845 to 1852, potato blight destroyed the main crop of the poor, about a million people died and as many again emigrated, yet grain and livestock continued to leave Irish ports. In the Bengal famine of 1943, wartime policy, hoarding and soaring prices killed millions. China's Great Leap Forward caused the famine of 1959 to 1961, in which tens of millions died, though estimates vary widely.

In 1981 the economist Amartya Sen argued in Poverty and Famines that famines usually happen because people lose the means to buy or grow food, not because food is absent. He later observed that no major famine had struck a working democracy with a free press. Today, famine warning systems track rainfall, prices and markets for early signs of crisis. A feast shows what a community can share; a famine shows what it chose not to.

Preserving Food: from Salting to the Fridge

Food starts to rot almost as soon as it is harvested or killed. Bacteria, moulds and yeasts feast on it, and for most of history a good harvest meant nothing if it could not last until the next one. Preserving food was therefore a matter of survival, and every method ever invented works in the same basic way: by making life difficult for microbes.

The oldest techniques used nature itself. Drying in sun and wind removes the water that microbes need. In the high Andes, people have made chuño for centuries by leaving potatoes out to freeze at night, thaw by day and be trampled dry, producing a food that keeps for years. Norse fishermen hung cod on racks in the cold Lofoten wind to make stockfish, a trade that records show flourishing in the Middle Ages. Salting draws water out by osmosis: Romans fermented salted fish into the pungent sauce garum, and medieval Europe ran on salted herring and bacon. Smoke adds both drying and chemicals that deter bacteria.

Fermentation recruits friendly microbes to crowd out harmful ones, producing acid or alcohol. Korean kimchi, German sauerkraut, yoghurt, cheese and soy sauce all work this way. On his first Pacific voyage in 1768, Captain James Cook carried barrels of sauerkraut, and his ships suffered little from scurvy, though historians debate how much the cabbage was responsible.

Heat and sealing came next. In 1810 the Parisian confectioner Nicolas Appert published his method of sealing food in glass bottles and boiling them, after a government call for better ways to feed armies. In the same year in Britain, Peter Durand patented the idea of using tin cans, and by 1813 the engineer Bryan Donkin was supplying canned meat to the Royal Navy. Nobody yet knew why it worked: Louis Pasteur's studies of microbes in the 1860s finally explained it.

Did you know? Early tin cans came without any way to open them; instructions suggested a chisel and hammer, and the first can opener was not patented until 1858.

Cold is the newest and most powerful method. Ice houses stored winter ice for summer use in Persia, China and English country estates. In 1834 Jacob Perkins patented a vapour-compression machine, the ancestor of every fridge, and mechanical refrigeration spread through breweries, meatpacking plants and ships in the late 1800s. Clarence Birdseye, inspired by Inuit fishermen in Labrador whose catch froze instantly in the Arctic air, developed quick-freezing, and his frozen foods went on sale in 1930. Today a global cold chain moves fresh food across oceans. Salt, smoke and the freezer are fighting the same enemy.

The Kitchen Through Time

The kitchen is the oldest workplace in the home. For hundreds of thousands of years it was simply a fire: a hearth on the floor of a cave or hut, ringed with stones, where meat roasted and pots simmered. Archaeologists find these hearths as patches of reddened earth, charcoal and burnt bone, and their position tells us how people arranged their lives around heat and food.

In the Neolithic town of Çatalhöyük in Turkey, around 7000 BC, each mud-brick house had a domed oven and a hearth set against one wall, beneath the rooftop hole through which people entered and smoke escaped. For thousands of years after, most households across the world cooked over a central hearth with a pot or cauldron. A medieval peasant family's daily pottage of grain, beans and vegetables bubbled in a single iron or clay pot, and smoke drifted out through the roof.

Not everyone had a kitchen at all. In Roman cities, many people lived in cramped apartments where open fires were dangerous, so they ate out. Pompeii had dozens of street counters, the thermopolia, with clay jars set into masonry for hot food. One excavated in 2019 and 2020 still bore paintings of ducks and a rooster, perhaps an early menu. The rich, meanwhile, had kitchens staffed by enslaved cooks. Great medieval households built enormous kitchens like the octagonal Abbot's Kitchen at Glastonbury, with a fireplace in each corner. In East Asia, the wok over a brick stove and the Japanese clay kamado cooked fast with little fuel.

Did you know? Pompeii's street-food counters were so common that many Romans may never have cooked a meal at home.

The modern kitchen began with closed stoves. In the 1790s the scientist Count Rumford designed enclosed fireplaces that used fuel far more efficiently. Victorian homes gained the cast-iron range, with ovens, a hot-water boiler and a hob, blackened weekly with polish by a servant or the woman of the house. Gas cookers spread through Britain in the late 1800s, followed by electric cookers, refrigerators and running hot water.

The great leap in design came in 1926, when the Austrian architect Margarete Schütte-Lihotzky created the Frankfurt Kitchen for social housing. Narrow, efficient and fitted with built-in cupboards, worktops and labelled storage drawers, it was planned like a factory workstation to save steps, and around 10,000 were built. Its descendant is the fitted kitchen found in homes worldwide. Today's open-plan kitchen has returned to where it started: the hearth at the centre of the home, with the fire now behind glass.

Clothes and Fashion

People are the only animals that dress. Clothing began as protection from cold, sun and thorns, but it quickly became something more: a way of showing who you are, where you belong and how much you can afford. Fashion, the restless change of styles, is just the latest chapter in a very long story.

Because cloth and leather rot, the earliest evidence is indirect. Geneticists have studied body lice, which live only in clothing; their split from head lice suggests that people were regularly wearing clothes by at least 80,000 years ago, though estimates vary. Eyed bone needles appear by around 40,000 years ago, a sign of tailored garments. At Dzudzuana Cave in Georgia, fibres of wild flax about 30,000 years old, some of them dyed, hint at early string and cloth.

Then come the rare, astonishing survivals. Ötzi, the man who died in the Alps around 3300 BC and was frozen in a glacier, wore a complete outfit: a bearskin cap, a coat of stitched sheep and goat hide, goatskin leggings, a sheepskin loincloth and shoes with bearskin soles stuffed with grass for warmth. In Egypt, the linen Tarkhan Dress, with pleated sleeves, has been radiocarbon dated to before 3000 BC, making it the oldest known woven garment. In China, silk was spun from the cocoons of domesticated silkworms, and for centuries the technique was a jealously guarded secret.

Did you know? Ötzi's clothes were made from the hides of at least five species: sheep, goat, cattle, brown bear and roe deer.

Clothes became a matter of law. Many societies passed sumptuary laws limiting who could wear certain colours, fabrics or furs: an English statute of 1363 set dress by rank, and Tokugawa Japan issued repeated edicts restricting merchants' finery. Purple dye from murex sea snails was so laborious that it became the colour of Roman emperors. Trade made fashion global: Indian printed cottons became so popular in Britain that Parliament banned most of them in 1721 to protect wool and silk weavers.

Industry and science then remade clothing. Mechanised spinning and weaving in the late 1700s made cloth cheap. In 1873 Jacob Davis and Levi Strauss patented riveted denim work trousers, the ancestor of jeans. Nylon, developed by DuPont in the 1930s, appeared as stockings in 1939 and 1940 and caused queues across America. Today clothes are cheaper and more plentiful than ever, and the environmental cost of fast fashion is a pressing question. Whatever we wear, we are still sending the same ancient message: this is who I am.

Home: from Longhouse to Semi

A home is more than a shelter. Its shape records who lived together, how they kept warm, where the animals slept and how much privacy anyone could expect. Archaeologists read houses from postholes, hearths and floor surfaces; historians add wills, building records and censuses.

Among the first great house types was the timber longhouse. Across central Europe around 5500 BC, early farmers of the Linear Pottery culture built houses up to about 40 metres long, framed by rows of massive posts. The posts rotted long ago, but the dark stains of their holes still mark out the plans, and whole villages can be mapped from them. Longhouses appeared again and again in different places: Viking families shared theirs with cattle at one end for warmth, and the Haudenosaunee of north-eastern North America built bark longhouses that held several related families.

Stone survives better. At Skara Brae on Orkney, around 3100 BC, villagers built snug houses half-buried in midden for insulation, each with a central hearth, stone box beds and a stone dresser facing the door. In Rome, crowds lived in insulae, multi-storey apartment blocks prone to fire and collapse; Augustus tried to cap their height. In Beijing, families lived around enclosed courtyards in the siheyuan, with the senior generation in the main hall on the north side, facing south towards the sun.

Did you know? Skara Brae lay hidden under sand dunes for over four thousand years until a great storm in 1850 stripped them away.

For centuries most people in Europe lived in one or two rooms around an open hearth. Chimneys, glass windows and upper floors gradually spread into ordinary English houses in the sixteenth and seventeenth centuries, a change some historians call the Great Rebuilding, though its timing is debated. The Industrial Revolution then packed workers into cheap terraces and back-to-back houses, with shared privies and little light. Public health laws from the 1870s required wider streets and better drainage, producing the long rows of by-law terraces still found in British towns.

After the First World War, the British government promised homes fit for heroes. The Tudor Walters Report of 1918 recommended cottages with gardens at low density, and the Housing Act of 1919 paid councils to build them. Between the wars, private builders added huge numbers of semi-detached houses along new roads and railway lines: two homes sharing one wall, with bay windows, front gardens and often a touch of mock-Tudor timber. Today most of humanity lives in cities, many in apartment blocks not unlike Roman insulae. The house has changed its shape many times, but never its purpose: somewhere to come home to.

The First Cities

A city is more than a very large village. Archaeologists look for a dense, permanent population, people who no longer grow their own food, monumental public buildings, and some way of keeping records and collecting tribute. The archaeologist V. Gordon Childe called this leap the "Urban Revolution" in 1950, and historians still debate which of his tests matter most, and whether a single revolution ever happened at all.

The earliest clues lie in tells, mounds built up from centuries of collapsed mud-brick houses. At Çatalhöyük, on the plain of central Anatolia, several thousand people were living by around 7100 BC in homes packed so tightly that there were almost no streets. Yet the site has no palace, no great temple and little sign of a ruler, so most scholars call it a very large town rather than a city.

The first true city is usually said to be Uruk, in southern Iraq. By around 3100 BC it had great temple precincts, armies of craftsmen and a ring of walls later credited to the hero Gilgamesh, running for roughly nine kilometres. Its rubbish heaps and storerooms yielded thousands of clay tablets, among the earliest writing anywhere, most of them accounts of grain, beer and labour.

Cities then appeared independently far away. Mohenjo-daro, in the Indus valley, was laid out around 2500 BC with baked-brick drains along its streets and the Great Bath on its citadel mound. In Peru's Supe valley, Caral raised platform mounds and sunken plazas by around 2600 BC, without pottery and, as far as we know, without writing. Shang kings ruled from Anyang around 1250 BC, where oracle bones record their questions to the ancestors. In the Valley of Mexico, Teotihuacan grew from about 100 BC into a metropolis of perhaps 100,000 people, laid out along the Avenue of the Dead. At Jenne-jeno in Mali, excavated by Roderick and Susan McIntosh from 1977, a cluster of specialist settlements grew from around 250 BC with no obvious palace, upsetting the old idea that African cities were imported from outside.

Did you know? At Çatalhöyük there were almost no doors at ground level: people climbed in through openings in the roof and used the rooftops as their streets.

Why did cities form? Surplus grain, trade, defence and religion all played their part, and the mix differed from place to place. The costs arrived with the benefits: crowd diseases, sharp inequality and the first tax collectors. Today more than half of humanity lives in towns and cities, and every one of them still runs on the bargain first struck in places like Uruk: give up your fields, and gain a crowd.

Pyramids and Monuments

People built monuments long before they built cities. At Göbekli Tepe in south-eastern Turkey, hunter-gatherers raised T-shaped limestone pillars carved with foxes, boars and vultures around 9500 BC, thousands of years before farming villages filled the region. Stonehenge in England went up in stages from around 3000 BC, and its smaller bluestones were hauled more than 200 kilometres from the Preseli Hills in Wales. A monument is a message to the future, and the people who make one rarely leave instructions.

The pyramid is the most famous answer to the question of how to make something last. Egypt's first was the Step Pyramid of King Djoser at Saqqara, built around 2650 BC and credited to his official Imhotep: six stone platforms stacked about 62 metres high. Within a century, builders had learned to fill in the steps and make true sloping faces. The Great Pyramid of Khufu at Giza, finished around 2560 BC, rose about 146 metres from more than two million blocks, and stayed the tallest structure made by human hands for over 3,800 years.

Who built it? The Greek historian Herodotus, writing some 2,000 years later, described gangs of 100,000 men forced to labour, and films later turned them into slaves. Excavations led by Mark Lehner and Zahi Hawass from the 1990s found the workers' town beside the plateau, with bakeries, breweries, heaps of cattle and fish bones, and cemeteries where labourers were buried with honour near their king. In 2013 papyri found at Wadi al-Jarf on the Red Sea proved to be the logbook of an official called Merer, recording boatloads of limestone shipped from Tura to Giza. They are the oldest inscribed papyri yet found.

Pyramids rose elsewhere, for other reasons. The ziggurat of Ur, built around 2100 BC, lifted a temple towards the gods on a stepped mud-brick mountain. In Nubia, today's Sudan, the rulers of Kush built steep, narrow pyramid tombs at Meroë from around 300 BC, and the region has more pyramids than Egypt. At Teotihuacan in Mexico the Pyramid of the Sun, about 65 metres high and built around AD 200, carried a temple on its summit rather than a burial chamber. In Cambodia, Angkor Wat was raised in the early 12th century as a stone model of the mountain at the centre of the universe.

Did you know? The largest pyramid on Earth by volume is at Cholula in Mexico, but it is so overgrown that it looks like a hill, and a church built in 1594 stands on top.

Monuments turn power into something you can see from a day's walk away. They also reveal the machinery behind it: quarries, boats, granaries, scribes and rations. A pyramid is a tomb, a work roster and a state's balance sheet, all set in stone.