Cheap iron pushed the rich toward silver and gold

Demand for ornament that marked rank raised metal production. Copper became widely available in Eurasia, iron followed in Africa and Eurasia by the early first millennium BCE, costs fell, and the metals moved into tools and weapons. The people who had used them for display turned to scarcer and showier materials, silver, gold and copper alloys. Weaving looks like the same story. Cloth may have gained its importance because the upper ranks of newly stratified societies wanted garments that announced and confirmed their position. The cotton of the Khartoum Neolithic in Sudan fits, since indirect evidence points to sacral chiefs among the Nilo-Saharan peoples living along the major waterways there. The Americas fit too, because the earliest cotton weaving there sits close in time to the rise of political and social stratification on the coast of Peru from the middle of the fourth millennium BCE. These were the first centuries of textiles, and the first in which what you wore told strangers who you were.

The Levisa rock shelter in Cuba holds a Lithic age deposit dated to 4190 BCE. It is among the earliest confirmed human occupations anywhere in the Caribbean islands. The people who left it worked stone, took what they needed from the rivers and the high ground behind them, and moved with the seasons rather than settling in one place. They were foragers, and the way they lived has to be kept separate from the Taino societies that European ships met almost six thousand years later. Those were farmers with villages, chiefs and ball courts, and they came out of a different tradition. This matters for how the region gets narrated. A Caribbean history that opens in 1492 treats the islands as empty until Europe arrives. A rock shelter in Cuba dated to 4190 BCE says the islands had been occupied for something like six thousand years by then, which makes the usual starting point a decision somebody took.

Hor-Aha, first or second king of the First Dynasty, sent his forces south and destroyed what remained of the Qustul state. The southern frontier of the Old Kingdom was fixed by that campaign and held for centuries afterwards. He did it wearing the White Crown that a Qustul ruler had worn before him, attended by the Horus falcon that had attended a Nubian king, carrying an idea of sacred kingship developed upriver in the country he was burning. The Old Kingdom that followed went on displaying its inheritance in plain sight. Its political institutions and its ritual observances kept the marks of the wider Middle Nile world they came out of, in the ceremonies around the king, in the handling of royal death, and in the claim that a ruler holds divine authority. Conquest ended the kingdom. It left the kingdom intact inside the conqueror's own practice, where it is still legible.

Three hundred kilometres southwest of Aswan, in country that is now open desert, there was a lake that filled in the rains. By the middle of the fifth millennium BCE the people who watered cattle there had turned the place into a ritual centre. They erected megalithic arrays, including a circle of stones that works as a calendar and five separate alignments, each pointed at the rising position of a particular star. Every material indication at Nabta Playa and across the wider region says the builders were Nilo-Saharan speakers, the same livestock-raising communities whose pottery and burial customs were moving north down the Nile. The date is the point. The Great Pyramid at Giza went up a full thousand years after these stones were set. The astronomy that later gets described as an achievement of the Egyptian priesthood was already being practised by African pastoralists in the desert, who read the sky closely enough to fix its motions in stone.