What was the effect of the Nizari Isma'ili split on the Fatimid Caliphate?

The Nizari Isma'ili split weakened the Fatimid Caliphate, leading to its eventual decline and fall.

The Nizari Isma'ili split was a significant event in the history of the Fatimid Caliphate, a Shia Islamic caliphate that spanned a large area of North Africa from the Red Sea in the east to the Atlantic Ocean in the west. The split occurred in the late 11th century, during a period of internal strife and external threats. The Nizari Isma'ilis, a sect of Shia Islam, broke away from the Fatimid Caliphate, leading to a significant reduction in the Caliphate's power and influence.

The split was precipitated by a succession dispute following the death of the Fatimid Caliph al-Mustansir Billah in 1094. His younger son, al-Musta'li, was appointed as the new Caliph, but this was contested by the elder son, Nizar, leading to a civil war. The Nizari Isma'ilis supported Nizar, and when he was defeated and killed, they refused to recognise al-Musta'li as the legitimate Caliph. This led to the formation of the Nizari Isma'ili state, with its own Imam and followers, separate from the Fatimid Caliphate.

The split had a profound impact on the Fatimid Caliphate. It not only lost a significant portion of its followers, but also its political and military strength. The Nizari Isma'ilis, who were concentrated in Persia and Syria, were able to establish their own strongholds and effectively resist Fatimid control. This further weakened the Fatimid Caliphate, which was already facing threats from the Seljuk Turks and the Crusaders.

Moreover, the split also led to a decline in the Fatimid Caliphate's religious authority. The Nizari Isma'ilis, with their own Imam, no longer recognised the Fatimid Caliph as the spiritual leader of the Shia Muslim community. This undermined the Caliphate's claim to religious legitimacy, further weakening its position.

In conclusion, the Nizari Isma'ili split was a major blow to the Fatimid Caliphate. It not only led to a loss of followers and territory, but also undermined the Caliphate's political, military, and religious authority, contributing to its eventual decline and fall.