The Nubian kings who Islamic states in fulfillment of the contract.

And there was a lack They sometimes refrained from fulfilling these conditions, and the Islamic states in Egypt were forced to send disciplinary campaigns and compel them to fulfill the contract.

Thus, the Arabs came into contact with Nubia and the Beja, a contact that facilitated passage and movement south, which provided an opportunity for Muslims to advance south, even to the kingdom of Alwa and near the current location of Khartoum, where the capital Soba was. From here, the Fatimid traveler Ibn Salim al-Aswani, who visited the region in 969 AD, found that many Arabs had mixed with the Nubians to the extent that a large number of them had spread the Arabic language, and they did not forget the Arabic language, as the Sudanese Yusuf Fadl Hasan mentioned, who tried in his writings to diminish the importance of Arabs, Arabism, Islam, and Muslims in Sudan in those eras.

However, the treaties and commitments that had been made between the Muslims and the Nubians and the Beja did not stop them from causing trouble on the southern borders of Egypt, and the sedition stirred up by the Beja did not end. Thus, only a few years passed after their return from Baghdad. And the Baqt was made every three years instead of being paid annually, yet they refrained from paying their obligations of the kharaj as stipulated by the treaty and launched a great revolt, killing a large number of Muslims working in the mining land. Not content with that, they raided Upper Egypt as was their custom. So the Abbasid Caliph al-Mutawakkil ordered the dispatch of a campaign against them led by Muhammad ibn Abd Allah al-Qummi in 241 AH / 854 AD. Al-Mutawakkil also ordered the governor Anisa ibn Ishaq al-Dabbi to provide him with men and provisions. From here, al-Qummi marched towards them with a force exceeding 20,000 soldiers (twenty thousand soldiers). There, in the mining land, Arabs from Rabia, Egypt, and Yemen joined them. Ships also brought them provisions via the Red Sea from the coast of Qulzum to the coast of Aidhab. The Egyptian Islamic campaign managed to defeat the Beja, and their king, "Ali Baba," requested peace on the condition that he pay the kharaj for the previous period of four years. Al-Qummi agreed with them.