The ledger of ancient exchange runs in Africa's favour

Count what left the continent. Watermelon and the bottle gourd from the Sudan belt. Muskmelon from the Horn of Africa. Cowpea, the country potato, roselle and tamarind out of West Africa. Pearl millet from the western and the eastern Sudan belt both. Sorghum and the lablab bean out of the eastern Sahara and the eastern Sudan. Finger millet from Cushitic speakers up in the Ethiopian highlands. The castor oil plant, most likely from Cushitic speakers in the Horn. And the donkey, from herders on the dry steppe and semidesert of the far eastern Sahara and the northern edge of the Ethiopian highlands. Thirteen items in all, moving out across the seventh to fourth millennia BCE, most of them well into Eurasia by 3000 or 2000 BCE. None of them came from the Mediterranean rim. They came from independent centres of innovation deep in the African interior. Africa gave the ancient connected world more than it received back, and that sentence still reads as a provocation.

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.

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.

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.