This project focuses on the economic and social history of Central and West Asia from the fifth to the seventh centuries CE, concentrating on the Sasanian Empire (Iran, Iraq, and the Caucasus), its fall in the mid seventh century, and the transition of its territory to the control of the early caliphate. Starting in the late fifth century (480’s) the encounter of the Sasanians with the Hephthalite kingdom, the project uses a wide range of sources for sketching a picture of the economic changes that characterise the Sasanian domains in the subsequent two centuries. The project evaluates the information provided by textual, archaeological, and numismatic evidence to study the monetary, economic, and political consequences of the Sasanian defeat at the hands of the Hephthalites. Starting with the payment of hefty war reparations to the Hephthalite Khaqan, the position of the Sasanians within the Eurasian world changes, occasioning a “western” shift in the empire’s political outlook and necessitating a series of deep Reforms in the sixth century. The rise of the Western Turk Empire in the same period also further affects the Sasanian position within the larger Eurasian economy, bringing about major changes in the imperial strategy, including a shift toward a more aggressive, war based policy in the eastern Mediterranean. The project posits that the consequent Sasanian-Byzantine Wars of the early seventh century appear within this context as a “control mechanism” for the deep changes the precede them, with significant social and political reverberations, among which are the early Islamic Conquests leading to the integration of the Sasanian domains into the Caliphate. The final results will be to better understand these changes, reforms, and wars within a longue durée setting and trans-Eurasian interactions and to provide a more comprehensive context for the circumstances that usher in “the medieval period” across Eurasia.