Riding the Monsoon: Geography and Iron Age Trade in the Indian Ocean
This paper exploits ancient textual sources to develop a database of ancient trade in the Indian Ocean and model trade in the region during the Iron Age. Wind-speed data is used to construct a gravity model of trade and is combined with detailed textual data from the Periplus of the Erythraean Sea to analyse historical development trends in the Indian Ocean. While distance was an important factor in maritime trade, the speed of travel was the defining feature with a substantially non-linear effect. Trade is shown to be lower between locations that are close together with similar export baskets, reinforcing an endowment-based, Ricardian specification of the gravity model for this period. Additionally, there is significant evidence for both export-led growth and an ancient version of the `resource curse'. Cities that export a greater variety of goods exhibited a significant increase in density during the period. Similarly, areas around cities with exports that relied more heavily on manufactures and artisanal goods grew at a faster rate than areas around cities that focussed more on cash crops.