Fatimid dynasty

The Fatimid dynasty (Arabic: الفاطميون, romanized: al-Fāṭimiyyūn) was an Arab dynasty that ruled the Fatimid Caliphate, between 909 and 1171 CE. Descended from Fatima and Ali, and adhering to Isma'ili Shi'ism, they held the Isma'ili imamate, and were regarded as the rightful leaders of the Muslim community. The line of Nizari Isma'ili imams, represented today by the Aga Khans, claims descent from a branch of the Fatimids. The Alavi Bohras, predominantly based in Vadodara, also claim descent from the Fatimids.

The Fatimid dynasty emerged as the leaders of the clandestine early Isma'ili missionary movement (da'wa) in the ninth century CE, ostensibly acting on behalf of a hidden imam, implied at the time to be Muhammad ibn Isma'il. The Isma'ili da'wa spread widely across the Islamic world, then ruled by the Abbasid Caliphate. In 899, the future first Fatimid caliph, Abdallah, proclaimed himself to be the expected imam, causing a rift in the Isma'ili da'wa as the Qarmatians, who did not recognize his imamate, split off. In the meantime, Isma'ili agents had managed to conquer large parts of Yemen and Ifriqiya, as well as launch uprisings in Syria and Iraq. Fleeing Abbasid persecution to Ifriqiya, Abdallah proclaimed himself openly and established the Fatimid Caliphate in 909. From there, the Fatimid imam–caliphs extended their rule over most of the Maghreb as well as Sicily, before conquering Egypt in 969. Founding Cairo as their new capital, for the next two centuries, the Fatimids would be based in Egypt and identified with the country. At their height, the Fatimids claimed control or suzerainty over much of North Africa, Sicily, Egypt, the Levant, the Hejaz, Yemen, and Multan.

The Fatimids' claimed pedigree of descent from Fatima and Ali was central to their legitimacy as the legitimate imams in an unbroken, divinely ordained line from Ali onwards. Their initial obscurity, and the publication of conflicting and incorrect genealogies by the first Fatimid caliph, Abdallah al-Mahdi Billah (known by the diminutive Ubayd Allah by his detractors), cast doubt on the accuracy of these claims, which were usually rejected by contemporary Sunni and Twelver Shi'a alike, who considered them impostors and usurpers. As a result, many sources into the 20th century referred to the Fatimids by the derogatory name Ubaydids.

Fatimid expansion into the Levant, and the ideological challenge that the ascendancy of Shi'a regimes represented, resulted in the Sunnis rallying around the Abbasid Caliphate in response, triggering the Sunni revival of the 11th century. Faced with internal turmoil, and the arrival of the Seljuk Turks and then the Crusades, Fatimid power began to decline in the later 11th century. the dynasty was saved by passing power to powerful military viziers, but this also meant that the imam–caliphs often were mere puppet rulers. The initial dynamism of the da'wa was diminished by bitter succession disputes, which resulted in large parts of the Isma'ili community, such as the Druze, Nizaris, and Tayyibis, breaking off from the Fatimid allegiance, and tarnished the prestige and authority of the dynasty. The last of the Fatimid imam–caliphs were powerless child rulers that were pawns in the hands of their viziers. The last of these viziers, Saladin, deposed the dynasty in 1171, after the death of Caliph al-Adid. The remaining members of the dynasty and their offspring were placed under house arrest in Cairo until their deaths; the last members of the dynasty died in the mid-13th century.