Each island holds a monopoly and trades on it

By the first millennium CE the Lesser Antilles were running an economy with specialists in it. Montserrat made beads. St Martin made stone celts. Other islands made neither and had both. Archaeologists separate producer from consumer by counting waste, since the manufacturing sites are buried in debris and the settlements that used the goods hold finished pieces alone. Mapping that distribution produces what Keegan and Hofman call a social geography, in which a given island holds an effective monopoly over a given mineral and trades on it. The arrangement let communities stay independent of one another while remaining necessary to one another. Each had a role that could be named, and the goods passing between them carried the terms of the relationship. The islands of the eastern Caribbean were an integrated system a thousand years before Europe arrived and reported finding scattered people living hand to mouth on whatever the sea happened to give them.

Arab armies took Egypt in 642 and pushed south against the Christian kingdoms of the Upper Nile. Nubia fought hard and had little gold or grain worth seizing, so in 652 the two sides settled on terms. No Muslim would enter the country. In return Nubia would hand over a fixed number of enslaved people every year, receiving other goods in exchange. The agreement was called the Baqt and it appears to have held for several hundred years. Under its shelter the kingdoms of Makuria, whose capital stood at Dongola, and Alwa, centred on Soba near modern Khartoum, built cathedrals and monasteries at Faras, Qasr Ibrim, Sai and elsewhere and covered their walls with paintings. This is one of the oldest recorded arrangements in which an African state agreed to deliver human beings on a schedule as the price of being left alone, and it ran for centuries before any European ship reached the Atlantic coast.

At the Canas site in Puerto Rico the Saladoid and Ostiones layers sit one above the other with a clean line between them, and the early conclusion drawn from that line was that two separate cultures had occupied the site in turn. The difficulty with that reading is that nobody could find anywhere for the second culture to have come from. No source region, no migration route. So the material was examined again, and the current view is that Ostionoid pottery grew out of the Saladoid tradition in the islands themselves, with recent argument pointing to the eastern Dominican Republic and the exchanges taking place there. Other evidence supports continuity. Stone toolmaking runs straight through the transition with no equivalent break. What changed was the pottery, and pottery is the loudest thing in an excavation. The change marks the beginning of a period in which the Greater Antilles broke into regions, each developing a look of its own.

At Cerrillo, in the west of Puerto Rico, there is a place where people went to work flint. It reads as a workshop rather than a village, since the ground holds the waste of tool manufacture, the flakes and rejected pieces that come off shaping a nodule into something usable. Cerrillo was busiest during the changeover into the Ceramic age, when pottery was being adopted and settlement was reorganising, and the flint had been quarried there before that. The evidence indicates people were taking nodules out of the same deposit back in the Archaic age. That continuity is the interesting part. A source of good stone gets found once and then used for as long as anyone needs stone, across changes in pottery, diet and social arrangement that archaeologists treat as boundaries between cultures. The people at the flint outcrop in the seventh century were going to a place their predecessors had gone to for centuries, for the same reason.