In this innovative and challenging study, Donald Ostrowski adds fresh and important insights to a pivotally important yet poorly understood subject--Mongol influence on Muscovy. Ostrowski considers here the outside origins and influences, as well as the indigenous origins and development, and shows that during the early period of Muscovy the dominant outside influences came through both Byzantium and the Qipchaq Khanate with its capital at Sarai. In considering these outside influences, Ostrowski has set out to study Muscovy as an integral and important part of world history.