The Islamic Conquest of Egypt

In 639 CE, Arab general Amr ibn al-As crossed into Egypt with an army of roughly 4,000 horsemen. By 642, he had conquered the entire country, taking the fortress of Babylon (near modern Cairo) and the great city of Alexandria — then still one of the largest cities in the Mediterranean world. The Byzantine garrison, weakened by years of conflict with Persia and undermined by religious disputes between the Coptic majority and the Greek Orthodox elite, offered limited resistance. Amr founded a new capital, Fustat (which would eventually grow into Cairo), near the apex of the Nile Delta. The conquest was one of the most consequential events in Egyptian history. Over the following centuries, Egypt gradually transformed from a predominantly Coptic Christian, Greek-speaking society into an Arabic-speaking, Muslim-majority one — though the Coptic community survives to this day as roughly 10% of the population. Egypt became a jewel of the Islamic caliphate, a center of learning and trade, and eventually the seat of the Fatimid Caliphate, which founded Cairo in 969 CE. The Al-Azhar mosque and university, established in 970, remains the most prestigious institution of Islamic learning in the world.