Of mice and merchants: trade and growth in the Iron Age

We study the causal connection between trade and development using one of the earliest massive trade expansions in prehistory: the first systematic crossing of open seas in the Mediterranean during the time of the Phoenicians. For each point on the coast, we construct the ease with which other points can be reached by crossing open water. This connectivity differs depending on the shape of the coast, the location of islands, and the distance to the opposing shore. We find an association between better connected locations and archaeological sites during the Iron Age, at a time when sailors began to cross open water very routinely and on a big scale. We corroborate these findings at the level of the world.