Despite their siege by the Arabs, Dongola from the Hadh and forced them to Islam. Perhaps this violence of resistance stemmed from the nature of the country and its geographical conditions. Its terrain allowed the kings and resisting elements to take refuge in fortified positions, to disappear at times and reappear at others from where the attackers did not expect them to appear. This perhaps explains the failure of the military expeditions that Egypt launched towards the south. Furthermore, its climatic conditions added another dimension, because these climatic conditions hardly differed from its topographical conditions and its general appearance of severity and drought, and the attackers' need for provisions and supplies, and the hardships they endured for that purpose. Therefore, the Egyptian campaigns were swift and fleeting, unable to stay long. Had they stayed longer, they would have achieved all their objectives. Hence, these first Arab campaigns did not intend a serious advance towards Nubia. Amr ibn al-As did not aspire to more than securing Egypt's southern borders and pursuing some fleeing Byzantine soldiers or commanders. Perhaps it was an exploratory campaign aiming to survey conditions in Upper Egypt. The campaign of Abdullah ibn Sa'd ibn Abi Sarh was merely a response to an armed aggression by the Nubians on Egypt's southern borders. Therefore, it is not unlikely that the Byzantines were behind these events of Nubian aggression on Egypt's southern borders after they tried to recapture Alexandria in 25 AH. Perhaps they incited the kings of Nubia to attack Egypt from the south to distract the Muslims from defending Alexandria in the north. Hence, the Nubians, in turn, were no less eager for an agreement than the Arabs, as their mother church in Egypt was in the hands of the Arabs, as well as