Al-Mansur Billah

Isma'il was born in early January 914 in Raqqada near Kairouan, the son of the second Fatimid caliph, Muhammad al-Qaim Bi-Amrillah, and a local slave concubine, Karima, who had once belonged to the last Aghlabid emir of Ifriqiya, Ziyadat Allah III.[1] When his grandfather, the founder of the Fatimid Caliphate, Abdullah al-Mahdi Billah (r. 909–934) died, he was designated as the secret heir (hujja, "proof") of his father; he was not publicly proclaimed as heir-apparent until 12 April 946, only five weeks before his father's death.[1]

The Fatimid realm found itself deep in crisis due to the revolt of Abu Yazid (943-947). However, after the unity of the rebels began to crack, Isma'il managed to put down the revolt with the help of the Berber Zirids. Following this victory he took the epithet al-Mansur, and built a new residence at al-Manṣūriyyah near Kairouan.

Al-Manṣur concerned himself with the reorganisation of the Fatimid state until the end of his reign. He resumed the struggle with the Umayyads of Córdoba in Morocco, and reoccupied Sicily, from where raids into Italy were recommenced. Rule in Sicily was reinforced through the installation of the Kalbids as Emirs.

Al-Mansur died after a severe illness on 18 March 953,[2] and left his realm to his son al-Mu'izz li-Din Allah (r. 953–975).

• Family tree of Muhammad#Family tree linking prophets to Imams
• List of Ismaili imams
• Ali ibn Muhammad al-Iyadi

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• Dachraoui, F. (1991). "al-Manṣūr Bi'llāh". In Bosworth, C. E.; van Donzel, E. & Pellat, Ch. (eds.). The Encyclopaedia of Islam, New Edition, Volume VI: Mahk–Mid. Leiden: E. J. Brill. pp. 434–435. doi:10.1163/1573-3912_islam_SIM_4938. ISBN 90-04-08112-7.
• Daftary, Farhad (2007). The Ismāʿı̄lı̄s: Their History and Doctrines (Second ed.). Cambridge: Cambridge University Press. ISBN 978-0-521-61636-2.
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• Kennedy, Hugh (2004). The Prophet and the Age of the Caliphates: The Islamic Near East from the 6th to the 11th Century (Second ed.). Harlow: Longman. ISBN 978-0-582-40525-7.