The government of Fustat had granted the Nubians a covenant of safety, but as soon as Amr ibn al-As left Egypt and was succeeded by Abdullah ibn Sa'd, they broke the covenant. When Sa'd ibn Abi Sarh was ruling Egypt, the Nubians broke the covenant of safety that Amr ibn al-As had given them. So, Abdullah ibn Sa'd ibn Abi Sarh launched an invasion of the kingdom of Makuria in 31 AH/652 CE, and the Arabs attacked Nubia for a second time. It appears that the Arabs had learned from the setbacks of the previous campaign and the failure it encountered during the time of Amr ibn al-As, and had prepared themselves thoroughly. From this, it seems that the Christian kingdoms of Nubia no longer had the capacity to withstand the Islamic tide that began to flow from Egypt through Nubia. It appears that this door had begun to open wide for the free flow of Islamic currents without any restrictions, after the Muslims had become acquainted with the land of Nubia, or Makuria, in the north, and the land of Alwa in the south. They used to frequent the lands of Nubia, passing through without settling. Thus, the Arabs came to know these lands through passing through. This passage and transit was for commercial purposes. Similarly, the Arabs became acquainted with the land of the Beja, who resided near Aidhab on the Red Sea. They also spread into the lands of Nubia and elsewhere, especially between the Nile and the Red Sea, in the lands extending from Aswan to Dongola approximately.

Abdullah ibn Abi Sarh's campaign penetrated deep into Nubia to the south and continued its advance until it reached the city of Dongola, the capital of the country, and besieged it fiercely. Their fortresses were bombarded with catapults, which the Nubians had not known before, and terror struck their hearts, forcing their king, "Kaledioth," to seek peace. Thus, the Islamic advance stopped at this point, and the Muslims were satisfied with the reconciliation and then returned. The Muslims dictated their terms to the king and concluded a peace treaty known as "Al-Baqz." It is possible that the Muslims agreed to the peace proposal suggested by the king because they were far from their homes, although this does not negate the fact that the Muslims established themselves far from Dongola, even in other places, and perhaps he saw that the Muslims did not intend to conquer the land of Nubia, but rather wanted to put an end to it.