Arab conquest of Egypt

Around December 639, a force under Amr ibn al-As, a commander of the caliph Umar, crossed from Palestine into Egypt with a few thousand men, with reinforcements arriving later. After defeating the Byzantines at Heliopolis in 640, the Arabs took the fortress of Babylon (in today's Cairo) in 641 and then Alexandria, which surrendered in 642. Egypt, long the breadbasket of Constantinople, passed to the Caliphate.¹²

Byzantium was exhausted. Egypt had been occupied by Sasanian Persia from about 618 to 628, and the empire had been restored only at huge cost. The Egyptian Church, which rejected the Council of Chalcedon, had been pressed by imperial officials, and many Egyptians felt little reason to fight for Constantinople. Treaties set tribute and taxes, including a poll tax on non-Muslims, and left much local administration and Christian worship in place.³

Amr founded Fustat beside Babylon as a military camp, the seed of later Cairo. Conversion and the use of Arabic spread slowly over centuries, and Copts remained a large minority. From Egypt, Arab armies pushed west along the North African coast. Egypt's Christian population stayed the majority for some time, and historians generally think a Muslim majority did not form until some centuries after the conquest, while Coptic survived as a spoken language into the medieval period. The conquest also ended Roman and Byzantine rule over a province held since Rome took Egypt after the death of Cleopatra.³⁴