Amru Ibn El-Aas, one of Mohammed's early proselytes, died in 663. He belonged to the Koreishites, and in early life was furiously opposed to Mohammed, ridiculing him in epigrams and satirical verses, and even attacking those of the new faith who had settled in Abyssinia. At last, however, he was converted, and his zeal in behalf of his new faith was as uncompromising as his opposition had been. The first two successors of the prophet, Abu Bekr and Omar, were chiefly indebted to his valor for the conquest of Syria. He carried his conquering arms into Egypt, and, at the head of only 4,000 men, took Pelusium and founded Old Cairo. He soon laid siege to Alexandria, and distinguished himself as much by his personal bravery as by his skill and conduct as a general. He was present in the assault, and in an attack on the citadel was taken prisoner with a faithful slave. Brought before the commander of the fortress, his slave, striking him in the face, ordered him to be silent in the presence of his betters; and this device saved his life by leading his conquerors to suppose him a person of no rank. He was sent back to the Mohammedan camp, with a proposition for a truce. This was refused, and the city was taken with a loss to the Arabs of 23,000 men.

Amru spared the city, but the orders of Omar subsequently caused the conflagration of the library. Amru became emir of Egypt, and his firm government conciliated the inhabitants. He projected a canal for uniting the waters of the Nile with the head of the Red sea. Having been recalled by Caliph Othman, the Alexandrians in his absence revolted, and surrendered the city to the Greeks. Amru returned, and once more reduced the city and spared the inhabitants. The caliph Moawiyah owed his accession to Amru, who declared for him in preference to his rival Ali.