A lake six hundred kilometres long once sat where the Sahara is

In the early Holocene the tropical African rain belt pushed north to the middle of the Sahara while the Mediterranean winter rains pushed south to meet it, and the desert turned green. Rivers ran off the Tibesti and Hoggar massifs and filled at least two great bodies of fresh water: Lake Fitri, and Lake Mega-Chad, which stretched well over six hundred kilometres from the site of the present Lake Chad north to the Tibesti. Early Nilo-Saharan speakers moved west out of the Nile country along these new waterways, and by the ninth millennium BCE they were working the shores of Mega-Chad with an intensive foraging economy built on large fish such as Nile perch and on hunting hippopotamus. The archaeologist J. E. G. Sutton named this the Aquatic Civilization of Middle Africa. It fed communities across a continental span for thousands of years, then vanished under the sand, leaving harpoon points, fish bones and the languages of the people who built it.

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.

The third independent invention of ceramics in the world belongs to Africa. By eleven and a half thousand years ago, around 9500 BCE, people in what is now Mali were making pots. The country in question lies south of the great bend of the Niger, and it falls inside the region where the ancestral form of Niger-Congo would have been spoken, the homeland of the largest language family on the continent today. Twelve thousand kilometres separate it from the Yangtze, which rules out anyone carrying the idea across. This is a dated, located archaeological finding and it has been available for years. Potters in western Africa were firing clay thousands of years before anyone in the Near East or in Europe did. The interesting question is no longer whether it happened. It is why a world history syllabus that has had this information for a generation still opens the story of ceramics in Mesopotamia and never gets to Mali at all.

West Africa produced its own inherited office, the kumo, which linguists trace back to proto-South Volta-Congo around the start of the sixth millennium BCE. Comparative ethnography across a wide band of the continent indicates the holder began as a clan ritual chief in clans that reckoned descent through the mother. His work was spiritual mediation: keeping the community on proper terms with the ancestors. Early on the office picked up civic duties too. The kumo moderated communal meetings, oversaw deliberation about law and custom, and spoke for his people in dealings with other communities. In later centuries the position gained real powers in a number of regions and turned into chiefship or kingship. Set against Nilo-Saharan sacral kingship, this is a different route to authority. One concentrates the spiritual and the temporal in a single divine figure. The other spreads authority across a network of ritual specialists whose standing rests on what they do. Africa was running both experiments at once.