The economy of conflict: How East Mediterranean trade adapted to changing rules, allegiances and demographics in the 10th--12th centuries AD

Seaborne trade increased in quantity and value despite the political and demographic upheaval in the East Mediterranean caused by the ongoing hostilities of the tenth through the twelfth centuries. In order to thrive, trade had to adapt to changing conditions, and thus, the story of the East Mediterranean economy in this period is the story of the modernization of the medieval economy. Critical to this adaptation was the recognition of the interdependence of the economies of all of the major players of the region. The Byzantine Empire, Italian merchant cities, the Islamic states, and the Latin States engaged in various conflicts, but they all depended on each other economically, and they used their unique advantages to enhance their own wealth. The Italian merchant cities traded their naval power for trade rights and other privileges with the Byzantine Empire and the Latin States, while the Muslim states encouraged the Italians to continue trading to overcome their lack of natural resources to manufacture weapons. Not only did the rulers of the time alter their course for economic benefit, but individual merchants altered their behavior, and local markets adapted independently of their central governance. Merchants navigated an obstacle course of moving armies, growing or declining cities, and governmental attempts to impose trade restrictions. Cities rose and fell in population and prominence according to their economic decisions and developed merchant quarters to support trade; evidence for these findings draws from a variety of textual and archaeological sources. In particular, underwater archaeology is opening a new avenue of study that can balance our current views of trade routes, cargos and merchant identities through the identification and exploration of shipwrecks.