 These early forays from a base in Egypt occurred under local initiative rather than under orders from the central caliphate.But when the seat of the caliphate moved from Medina to Damascus, the Umayyads (a Muslim dynasty ruling from 661 to 750) recognized that the strategic necessity of dominating the Mediterranean dictated a concerted military effort on the North African front.In 670, therefore, an Arab army under Uqba ibn Nafi established the town of Qayrawan about 160 kilometres south of modern Tunis and used it as a base for further operations.