The Holocene brought disruption, and disruption produced farming

When the Younger Dryas ended around 9700 BCE, climate shifted across much of the world, natural environments changed with it, and people had to rework how they obtained food. The response that defines the following four millennia was a slow, cumulative turn toward deliberately protecting and tending particular food sources. That meant the first cultivation of food plants, and in several regions the protection and herding of animals. The change did not begin in one place and radiate outward. It began independently in Africa, in the Levant, in China, in New Guinea and in Mesoamerica, everywhere for the same reason: the old way of feeding people had stopped working and something had to replace it. The Holocene did not arrive bearing abundance. It arrived bearing disruption, and the largest transformation in the history of the species came out of it. The people who made it were feeding their families in a world whose rules had changed under them.

Trinidad stayed joined to the South American mainland until the Holocene, and the consequences are still visible in what lives there. Its plants and animals are continental in range, and the island holds a long list of species that never reached the rest of the Antilles. It covers about four thousand eight hundred square kilometres, which makes it the sixth largest in the chain. Most of it is low hills and badly drained lowland, with a rough northern coast as the exception. That combination of position and biological range is why archaeologists routinely call Trinidad the gateway to the Caribbean. It is worth being precise about what the label means. Anything moving out of the Orinoco country and into the island chain had to come this way, so the settlement history of every island downstream begins with what people were doing here. A Caribbean that starts in 1492 skips the door and describes only the room.

From 6000 BCE the peoples of the middle Nile shared far more than an economy. A body of common ideas and ritual practice took hold from south of the Nile confluence all the way north into the country where the Old Kingdom would later be founded. The people involved did not speak one language. As far north as the latitude of Aswan they spoke Eastern Sahelian tongues, a branch of Nilo-Saharan. From Aswan down to El-Badari in Middle Egypt they spoke dialects of what would become ancient Egyptian. The convergence went straight across that boundary and produced shared pottery styles, shared ceremonies and shared assumptions about the world on both sides of it. So the culture area was bilingual from the start, and the civilisation that grew out of it carried both inheritances. Egypt spoke an Afrasian language and practised a great deal that had come upriver from Nilo-Saharan speakers over three thousand years of contact.

Anthropologists building their discipline in the nineteenth century kept finding regions where peoples of quite different origins had spent centuries in contact and had come to share deep features of culture, well past the superficial. Upper Egypt and the eastern Sudan belt were such a region from the sixth millennium BCE onward. Ehret calls the long south to north stretch the Middle Nile Culture Area. The label changes the question of Egyptian origins. Egypt did not come out of one ethnic group or one language community. It came out of a zone of sustained interaction among peoples with different linguistic and historical backgrounds, who over thousands of years of contact built a common stock of practices, ritual forms and material traditions. That makes Egyptian civilisation a regional outcome. To follow it you have to look south, into Nubia and Sudan, because half the culture area lay there and so did the origins of much that museum labels now file as distinctively Egyptian.