Byzantium and the Muslim world coexisted for more than eight centuries as rivals and partners. The emergence and subsequent evolution of the Islamic world can hardly be correctly understood without taking account of the Byzantine legacy there, as well as subsequent constant flow of cultural information from Byzantium to the East. Likewise, it is impossible to imagine Byzantine culture after the 630s without the constant presence of the Muslim world on its political, cultural and economic horizons. Moreover, for most of its history, Byzantium stood facing the Persian and Arab East, which retained and increased its high cultural potential, with its back to the poor and barbarised West. It is true that Byzantium adopted relatively little from the Muslim world, especially in comparison with the Byzantine contribution to Islamic cultures. Byzantium contributed more to other cultures than it took from them. Nonetheless, some of the literary, scientific, occult, economic and technological achievements of the Muslim world were transferred to Byzantium, as will be discussed later in this chapter. Therefore we must consider whether we can define these eastern influences upon Byzantine culture as specifically Islamic ones; or, to put the question more provocatively, can we talk of a sort of latent ‘Islamisation of Byzantium’ in the course of Byzantine-Oriental interchange?.