Before writing.

Mesopotamia is a name the Greeks gave the land between two rivers — the Tigris and the Euphrates. Today it is mostly Iraq, with edges in Syria, Turkey, and Iran. The lower third of this strip, where the rivers slow and braid into marshlands before reaching the Persian Gulf, is where our story begins.

The climate is hot, dry above ground, wet below. The two rivers flood every spring with snowmelt from the mountains of Anatolia. Between floods, the land is silt that crops will grow in if irrigated. Dig a canal — and the desert blooms.

What we today call the Sumerians did not appear on an empty stage. Ten thousand years before them, in the foothills of the Fertile Crescent — modern Turkey, Syria, Iran — a handful of communities had made the slow decision to stay put. They planted wild wheat and barley near their settlements. They tamed the sheep, the goat, the pig. They built houses of mud-brick and erected, at places like Göbekli Tepe and Çatalhöyük, the first monumental enclosures in human history. We call this the Neolithic Revolution. It took five thousand years. By the seventh millennium BCE, the descendants of those highland villagers had begun moving down into the alluvial plain, into the country between the rivers. By the time the Sumerians enter the record, four thousand years later, that country has been farmed and worshipped in by people whose names we have lost.

Before there was writing, before there was Sumer, there was the Ubaid culture, around 5500 to 4000 BCE. The Ubaidans built mud-brick villages, dug the first irrigation canals, fashioned painted pottery, and erected modest temples. At Eridu — which later Sumerian tradition will remember as the first city to receive kingship from heaven — the earliest temple layers are theirs. They are anonymous to us. We do not know what language they spoke, what they called themselves, what gods they served by what names.

In the late fourth millennium, something happens. Settlements grow larger. By around 3300 BCE the city of Uruk — built on the marsh — may hold forty thousand inhabitants. That is not many by modern standards; in 3300 BCE it is more people than have ever lived in one place. The centre of Uruk is a complex of temples. The temples manage the economy. The economy is too complicated for human memory.

A scribe in one of those temples picks up a piece of wet clay, sharpens a reed, and presses a mark. The mark stands for a thing — a measure of grain, a particular official, a name. Then another mark, and another. The scribe is not writing literature. He is doing accounting. But he has, almost incidentally, invented the technology that will let his civilization speak to ours.

These people called themselves sag-gíg-ga — "the black-headed ones." Their language was Sumerian. It is a language isolate: it belongs to no known family, has no surviving relatives, and we have no idea where it came from. The Sumerians did not see themselves as a single people but as the citizens of a dozen city-states — Uruk, Ur, Eridu, Lagash, Nippur, Kish, Umma, Adab. They were proud, jealous, competitive, religious, and unstoppably inventive.

They invented urban civilization. They invented the wheel and the sail. They invented mathematics in base sixty, which is why we still cut hours into sixty minutes and circles into three hundred and sixty degrees. They invented epic poetry, the legal code, the temple economy, the irrigation district. They invented writing — not once but several times, as the script evolved from pictograms toward syllabic signs.

What they did not invent — what was already there when they arrived — was the world. The Ubaid villages, the rivers, the marsh birds and the desert wind, the gods who lived in the mountains. The Sumerians built on a stage that was already set.

This book is what they wrote, in the order they wrote it. Every claim that follows rests on a tablet of clay, recovered from the silt of southern Iraq, deciphered over the last two centuries, and read here in translation. Where we are confident, we say so. Where we are not, we mark our uncertainty.

The story begins around 3300 BCE, in Uruk, with marks pressed into clay.