al-Mansur bi-Allah

Born Isma'il in January 914 (302 AH) at Raqqada, a palace town near Kairouan in Ifriqiya (roughly modern Tunisia), al-Mansur bi-Allah ("the victor through God") was the third caliph of the Fatimid dynasty, the Isma'ili Shia state that had risen in North Africa. In Isma'ili belief he is also counted as the thirteenth imam, the divinely-guided leader of the community; Sunni sources record him as caliph but do not accept that imamate. He came to power at a moment of acute crisis. A Kharijite Berber preacher, Abu Yazid, had overrun Ifriqiya and was besieging the Fatimid capital, al-Mahdia. According to the sources, al-Mansur's father al-Qa'im died in May 946 while the revolt raged, and al-Mansur kept the death secret, governing in his father's name and styling himself "Sword of the Imam" until he had taken the field, broken the rebels outside Kairouan, and pursued them into the Hodna mountains, where Abu Yazid was captured and died in August 947. Only then did he proclaim his own caliphate. To mark the victory he built a new royal city, al-Mansuriyya (locally Sabra), just outside Kairouan, entering it in 948. Reportedly often gravely ill, he nonetheless governed actively and appeared in public, unlike his reclusive father, and was remembered as popular in Kairouan. He died on 18 or 19 March 953 (341 AH) and was succeeded by his son al-Mu'izz, under whom the Fatimids would conquer Egypt and found Cairo.