Iron, sheep and the word for sheep travelled the same rivers

What is known about early commerce in the Congo basin rests largely on work by Jan Vansina and Kairn Klieman. The best documented stretch is the past two thousand years, and Klieman argues that the long-distance transport of goods in the region very likely began early in the first millennium BCE. The routes carried more than cargo. Ironworking spread along them from the Western Rift westward and southwestward during the middle and later part of that millennium. Sheep spread out of the African Great Lakes region the same way. One line of that spread can be followed through a single word, the term for sheep handed from language to language, which travelled west from Central Sudanic speakers living in the far southeast of what is now South Sudan. So the rivers moved goods, technique, livestock and vocabulary together across thousands of kilometres of forest, while the West African trade belt was expanding and the Garamantes were rising in the Sahara.

Late in the Archaic Age the traffic grew heavier between the islands and the Isthmo-Colombian mainland of Central and South America. Goods moved, and so did people and ideas. Keegan and Hofman describe these routes as lifelines running back to the communities the islanders had come from, which is a precise way to put it. A small population scattered across islands needs contact to stay viable, socially and culturally and in the plainest biological sense, and the mainland connection supplied it. The archaeology of the period looks different from one island to the next, and the authors read that variation as people adjusting to the particular place they had landed in. What this era built was the framework the later ceramic age villages would use. The settled farming communities that eventually filled Hispaniola did not appear out of nowhere. They inherited routes, relationships and habits of movement that had been in service for centuries.

The spread of the early iron smelting sites carries two implications. The first concerns place. The pattern of the distribution makes it likely that the people who worked out the technology lived somewhere in the fifteen hundred kilometres of woodland savanna between central Nigeria and the far northwestern fringe of East Africa. The second concerns time. Sites were already scattered across that enormous stretch three thousand years ago, and a technology takes generations to travel that far, so the founding workshops should date centuries before 1000 BCE. Both expectations have since been tested. In the last two decades archaeologists have found earlier African ironworking than anything previously recorded, and the finds sit inside the predicted zone. Ôboui, in the western Central African Republic, is one of them. This is the pattern that keeps repeating in Ehret's field. A prediction is made from vocabulary and distribution, someone digs in the indicated place, and the dates come back older than the standard account allows.

The evidence is indirect and it points to small states in Aïr, in West Africa, by 1000 BCE or earlier. The Nok region of Nigeria appears to have held an early strong state during the first millennium BCE, and its wealth most likely came from trading the metals found in its territory. Nok is famous for something else. Its terracotta heads and figures are among the earliest known figurative sculpture in West Africa and they sit in museums around the world, captioned as art and nothing more. The political economy behind the workshops goes unmentioned. Sculpture of that quality in that quantity implies patrons, and the patrons were living off control of metal and the trade in it. Together with Aïr, the finding puts political complexity in the Sudan belt at 1000 BCE or earlier. That is contemporary with the first Iron Age states around the African Great Lakes, and centuries before the gold trade that made Ghana, Mali and Songhay rich.