The Islamic call to their religion among the Nubians during their passage through Nubia was not confined to this. Some Islamic groups, following the dam construction project in 1961 AD, indicate Islamic graves dating back to the 10th and 11th centuries. Some were found in the Kalabsha area, dated 562 AH, and others were found in Ad-Derr, dated 1026 AD. This is in addition to thousands of Arab graves also found in the Halfa and Second Cataract areas, dating back to the early 10th and mid-11th centuries AD. This indicates the presence of Muslim communities in that Christian society from an early period of Islam's entry into Africa, and that these communities played a role in calling for Islam in these lands. Al-Masudi also mentioned that some Muslims from Aswan bought many estates within Nubian territory, and therefore there was no longer a need to annex or incorporate them into Islamic lands. As for the Beja or the Beja people, Muslims showed indifference to them following their invasion of Nubia in 1032 AH / 1041 AD, led by Abdullah bin Saad bin Abi Sarh. While the Muslims' interest in Nubia was of great importance, Ibn al-Hakam says, "The Beja gathered for him on the banks of the Nile as he was returning. He asked about them and was informed of their location, so he underestimated them and proceeded, leaving them without any treaty or peace. The first to make peace with them was Abdullah bin al-Hijab." However, the greater concern for these people was not in the Arabs' interest. After a period of no more than seventy-three years, these people found themselves capable, which prompted them to launch a raid on Egypt in 1077 AD / 725 AH. At that point, the Arabs became aware of their danger, as the sources recall for the first time a raid carried out by these Beja, who are the inhabitants of the desert.