Trade, Merchants and the Lost Cities of the Bronze Age

We analyze a large data set of commercial records produced by Assyrian merchants in the nineteenth century BCE. Using the information from these records, we estimate a structural gravity model of long-distance trade in the Bronze Age. We use our structural gravity model to locate lost ancient cities. In many cases, our estimates confirm the conjectures of historians who follow different methodologies. In some instances, our estimates confirm one conjecture against others. We also structurally estimate ancient city sizes and offer evidence in support of the hypothesis that large cities tend to emerge at the intersections of natural transport routes, as dictated by topography. Finally, we document persistent patterns in the distribution of city sizes across four millennia, find a distance elasticity of trade in the Bronze Age close to modern estimates, and show suggestive evidence that the distribution of ancient city sizes, inferred from trade data, is well approximated by Zipf's law.