The importance of the Mongols’ impact on the Rus lands has been recognised by many scholars, but its precise nature and extent is very contentious. While diverse opinions exist on the origins and development of Muscovy, the author argues that no society arises ex nihilo and that Muscovy is no exception. Donald Ostrowski considers here the outside origins and influences, as well as indigenous origins and development, in order that the reader may gain a clearer understanding of Muscovy as a political entity, its political institutions and political culture. He shows that during the early period of Muscovy (1304–1448) the ecclesiastical and secular institutions were affected by two different outside influences, Byzantium and the Qipchaq Khanate, respectively. In considering these outside influences, he has set out to study Muscovy as an integral and important part of world history.