Three ancient commercial revolutions solved one problem differently

Long-distance exchange systems emerged in several parts of the ancient world out of different social arrangements, and the differences show in what each one built. Across the western and central Sudan the revolution produced commercial towns and classes of merchants and artisans with no centralising state above them. In the Congo basin it ran on river networks and on societies whose membership crossed political lines. Around the Mediterranean it produced maritime commerce and coined money. The common features are easy to list: professional traders, production aimed at exchange, towns growing at the junctions, and institutions to keep goods moving across other people's territory. The problem was the same everywhere, which is how to move goods reliably over distances no single community controls. Each answer carried the marks of the people who worked it out. Studying one of them alone loses the pattern, and studying the pattern without Africa gets it wrong.

Horizon I on Martinique produced some of the earliest radiocarbon dates in the West Indies for the Cedrosan Saladoid, the pottery-making farming people who moved north into the islands from the South American mainland. Rouse treats the date as the opening of a long demographic change rather than a single landing. The islands were already occupied by Archaic-age bands, smaller groups who fished, gathered and hunted and who did not farm. Over the following centuries the farmers displaced them. Martinique sits in the middle of the Lesser Antilles, on the road running from the mouth of the Orinoco up the arc towards Puerto Rico and Hispaniola, and anything travelling that road passes it. I put a Martinique radiocarbon date on a Haitian timeline because the people the Spanish met on Hispaniola in 1492 came out of this movement. Their arrival is datable, gradual and about two thousand years long. Haiti has an indigenous beginning that predates every European in the story.

Words for iron and for the work of the forge spread eastward across central Africa until they stopped in the west of South Sudan, along what is now the Ethiopian border. They stopped because another body of ironworking terms was coming the other way, southward out of the northern Ethiopian highlands. The two met in eastern South Sudan around the middle of the first millennium BCE. Each set carries its own words for the furnace, the smith and the tools, and each traces back to a different chain of transmission, one African in origin and one reaching the highlands from the Middle East across the Red Sea. Had iron been born once in Anatolia and radiated outward from there, the vocabulary across this whole region would descend from a single root. Instead there are two lexical systems running into each other from opposite directions, thousands of kilometres from where either began. That meeting place is where the single origin theory stops working.

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.