Gold made Naqada matter. The eastern desert above the town was rich in it, and Naqada, with its facing town of Koptos across the river, sat where that gold entered the trade routes of the Nile valley. Wealth bred specialization. As farmers along the floodplain produced more grain than they needed, surpluses freed other people to become potters, stoneworkers, and metalsmiths - and to trade. The result was a society more economically advanced and diversified than anything in contemporary Lower Egypt, the Delta region to the north. Goods flowed in from astonishing distances: obsidian from Ethiopia, shells, cedar from Lebanon found in the tombs at nearby Nekhen. The Golden Town was a hub, and hubs grow complex. Out of that complexity came the first stirrings of kings.

We know this culture in three phases, and we owe the divisions to one obsessive man. In 1894 the British Egyptologist William Matthew Flinders Petrie excavated the Naqada cemeteries and faced a problem: how do you date graves with no inscriptions? His answer changed archaeology. By tracking how pottery styles shifted - a handle here, a wavy line there - he arranged the burials into a relative sequence, a technique now called seriation. From it came the three periods still used today. Naqada I, around 3900 to 3650 BC, gave us elegant black-topped red pots. Naqada II, to about 3300 BC, spread the culture across Egypt and brought the first metalworking. Naqada III, the final phase, carried more elaborate grave goods, the first true pharaohs - and writing.

The objects from these sites are intimate in a way monuments never are. One cooking pot, analyzed in a lab thousands of years later, still held the chemical trace of a meat stew sweetened with honey. At Tell el-Farkha in the Delta, archaeologists found a brewery with thirteen vats lined up in a row, fenced off from ordinary houses - industrial beer-making in the fourth millennium BC. Flint knives carried handles carved with worshippers and scenes from nature, the finest reserved for the elite. And on small vessels appear the earliest forms of Egyptian writing: simple pictograms, used not for poetry or prayer but to track trade and tally goods. The Naqada people were doing the unglamorous work of building a state - accounting, brewing, organizing - and inventing the tools to do it.

Scholars increasingly see the Naqada culture as deeply rooted in Africa, part of a Nile valley world whose social customs and religious ideas became the foundation of pharaonic Egypt. Studies of the people themselves - their skeletons and skulls - point to close affinities with other long-resident populations of northeastern Africa, including the Nubians to the south and groups of the Horn of Africa, rather than to migrants from elsewhere. The picture that emerges is of continuity: a population descended from the long-term inhabitants of this part of the world, slowly knitting villages into something larger. Naqada itself never became a great capital. But its final phase flows directly into the moment Egypt was unified under its first kings. Stand at this bend in the river and you are standing where a civilization was still deciding what it would be.