This dissertation investigates the growth and decline of a major Mediterranean commercial economy at the crossroads of Christian Europe and the Muslim Middle East from 1100 to 1400. New and old evidence uncovers the transformation of the commercial economy of the Byzantine Empire in its relations with the Middle East, western Europe, and Crusader principalities established in Byzantium's ruins. Ultimately, this work helps identify and understand the economic roots for enduring divisions between East and West, and it is unique in observing from Byzantium's perspective the transformation of the Middle East--the economic dynamo of the ancient and medieval Mediterranean.
