Christian and Islamic influence
Medieval Christian kingdoms
The 200 years from the fall of Kush to the middle of the 6th century is an unknown age in the Sudan. Nubia was inhabited by a people called the Nobatae by the ancient geographers and the X-Group by modern archaeologists, who are still at a loss to explain their origins. The X-Group were clearly, however, the heirs of Kush, for their whole cultural life was dominated by Meroitic crafts and customs, and occasionally they even felt themselves sufficiently strong, in alliance with the nomadic Blemmyes (the Beja of the eastern Sudan), to attack the Romans in Upper Egypt. When this happened, the Romans retaliated, defeating the Nobatae and Blemmyes and driving them into obscurity once again.
When the Sudan was once more brought into the orbit of the Mediterranean world by the arrival of Christian missionaries in the 6th century ce, the middle course of the Nile was divided into three kingdoms: Nobatia, with its capital at Pachoras (modern Faras); Maqurrah, with its capital at Dunqulah (Old Dongola); and the kingdom of ʿAlwah in the south, with its capital at Sūbah (Soba) near what is now Khartoum. Between 543 and 575 these three kingdoms were converted to Christianity by the work of Julian, a missionary who proselytized in Nobatia (543–545), and his successor Longinus, who between 569 and 575 consolidated the work of Julian in Nobatia and even carried Christianity to ʿAlwah in the south. The new religion appears to have been adopted with considerable enthusiasm. Christian churches sprang up along the Nile, and ancient temples were refurbished to accommodate Christian worshippers. After the retirement of Longinus, however, the Sudan once again receded into a period about which little is known, and it did not reemerge into the stream of recorded history until the coming of the Arabs in the middle of the 7th century.
After the death of the Prophet Muhammad in 632 ce, the Arabs erupted from the desert steppes of Arabia and overran the lands to the east and west. Egypt was invaded in 639, and small groups of Arab raiders penetrated up the Nile and pillaged along the frontier of the kingdom of Maqurrah, which by the 7th century had absorbed the state of Nobatia. Raid and counterraid between the Arabs and the Nubians followed until a well-equipped Arab expedition under ʿAbd Allāh ibn Saʿd ibn Abī Sarḥ was sent south to punish the Nubians. The Arabs marched as far as Dunqulah, laid siege to the town, and destroyed the Christian cathedral. They suffered heavy casualties, however, so that, when the king of Maqurrah sought an armistice, ʿAbd Allāh ibn Saʿd agreed to peace, happy to extricate his battered forces from a precarious position. Arab-Nubian relations were subsequently regularized by an annual exchange of gifts, by trade relations, and by the mutual understanding that no Muslims were to settle in Nubia and no Nubians were to take up residence in Egypt. With but few interruptions, this peaceful, commercial relationship lasted nearly six centuries, its very success undoubtedly the result of the mutual advantage that both the Arabs and the Nubians derived from it. The Arabs had a stable frontier; they appear to have had no designs to occupy the Sudan and were probably discouraged from doing so by the arid plains south of Aswān. Peace on the frontier was their object, and this the treaty guaranteed. In return, the kingdom of Maqurrah gained another 600 years of life.