The Fatimids claimed descent from Fatima, the daughter of Mohammed.
As partisans of Ali, Fatima's husband, they were Shi'ites and they became leaders of the Isma'ili movement that began to organize the overthrow of the Abbaside caliphate. By 911, their leader who called himself al-Mahdi had been proclaimed the rightful caliph - or imam as the Shi'ites preferred.
The Fatimids conquered northern Africa and in 972 conquered Egypt where they founded a new capital, al-Kahira (Cairo), and established the famous university mosque al-Azhar.
The Fatimids ruled from Tunesia to Syria but after about 1060 Fatimid power declined and their rule was confined to Egypt. On the death of the last Fatimid caliph in 1171, Egypt again returned to the Sunni fold.
Sunni / Shia Split