Sahel towns grow wards for weavers, tanners, potters and smiths

Before the second millennium BCE was out, the trading regions of West Africa began to link up: Tichit, the inland delta of the Niger, and the Air massif. Across the Sahel of present-day Mali a new kind of town grew out of clusters of manufacturing villages. One ward held families weaving cotton cloth for sale, cotton weaving having been established in West Africa by the end of that millennium. Another held leather workers, another professional potters. When iron reached this far west during the first millennium BCE, each town added a ward of smiths. The fifth group were merchants, who carried the town's output to distant buyers and financed its carriage. Dia, on the western side of the inland Niger delta, dates from the close of the second millennium BCE. Houlouf on Lake Chad grew into a polity and a junction. Archaeologists have located several hundred probable town sites along nearly two thousand kilometres of the western and central Sudan belt.

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.

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.