Farming systems invented separately begin to meet and trade parts

Between roughly 6000 and 3000 BCE the farming systems of the world stopped developing in isolation. Peoples who had worked out their own crops and their own herds moved into new country and carried their methods with them, and systems that had been invented separately in distant regions came into contact. What followed was traffic. Seeds, livestock, tools and techniques passed between communities with no common ancestry and no shared language, and every transfer changed the economy that received it. Christopher Ehret calls this the era of agricultural exchange, and he puts African farmers inside it as suppliers. The Sahara, the Sahel, the Ethiopian highlands and the West African forests each sent domesticated plants and herding practice outward into neighbouring economies while taking in crops from the Near East and East Asia. I keep this on a Haitian timeline because the received account still runs agriculture outward from one Fertile Crescent hearth into a waiting world, and that story trains people to expect Africa at the receiving end of everything.

Barrera-Mordan, in the Dominican Republic, is one of the sites that forced archaeologists to move the date of human arrival in the northern Caribbean. The material there is a stone-working complex built on flaked tools struck from cores, and it dates to around 4000 BCE. The people who made it belong to what is labelled the Lithic age. They had no pottery, and they should not be confused with the ceramic-producing groups who reached the islands thousands of years afterwards and are far better known. What the assemblage records is a specialised adaptation, worked out for a set of islands with particular stone, particular coastlines and particular food. Sites like this are how the initial migration routes from the surrounding mainland get mapped, because the tool types are the trail. Hispaniola, the island Haiti shares, was inhabited about six thousand years ago by people who knew exactly what they were doing with rock.

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.

The First Dynasty royal tombs at Abydos hold more than kings. Around them lie the graves of retainers and high-status people put there to accompany the ruler and look after him afterwards. Hor-Aha has thirty-six such burials. His successor Djer has as many as three hundred and eighteen. Djet has one hundred and fifty-four, and Den, the fifth ruler, has one hundred and thirty-five. The practice was neither confined to Egypt nor started there. It appears equally early further south, it was still going in the second millennium BCE at the height of the Kerma kingdom on the Upper Nubian Nile, and it recurs across a long line of Nilo-Saharan-speaking or Nilo-Saharan-influenced states in the Sudan belt, from pre-Christian Nubia to the Wagadu empire of the Ghana in the ninth century CE. Egypt is one branch of that tradition. It kept retainer burial for a few generations and then let it go.