Al-Musta'li

Here is an improved memorial biography of al‑Mustaʿlī based strictly on well-supported historical facts:

Abū al‑Qāsim Aḥmad ibn al‑Mustanṣir, better known by his regnal name al‑Mustaʿlī biʾllāh, served as the ninth Fatimid caliph and the nineteenth imam of the Mustaʿli branch of Ismaili Shi‘ism. He was born in Cairo, with most reliable sources indicating his birth occurred on 15 or 16 September 1074 (en.wikipedia.org). Some traditions suggest alternate dates in 1075 or 1076, but the 1074 dates are the most consistently reported (islamansiklopedisi.org.tr).

Following the death of his father, Caliph al‑Mustansir Billah, in late December 1094, al‑Mustaʿlī ascended the caliphate with the support of the powerful vizier al‑Afdal Shahanshah, who effectively controlled the administration (islamansiklopedisi.org.tr). His accession bypassed the customary claim of his elder brother Nizār, whose rebellion was suppressed; Nizār was captured and died soon after, resulting in a lasting schism within the Ismaili community between the Mustaʿli and the Nizari branches (en.wikipedia.org).

During al‑Mustaʿlī’s reign (1094–1101), Egypt entered a period of relative stability under the stewardship of al‑Afdal, while external challenges mounted. The First Crusade arrived in the Levant, capturing Jerusalem in July 1099 and achieving a major victory over the Fatimid forces at the Battle of Ascalon in August 1099 (en.wikipedia.org). These events marked the growing pressure on Fatimid holdings in Syria and Palestine during his rule.

Al‑Mustaʿlī died in Cairo in December 1101, most likely on 11 or 12 December, with some sources citing 10 December. There were contemporaneous rumors that he may have been poisoned by al‑Afdal, though such claims remain speculative (en.numista.com). He was succeeded by his son, al‑Amir bi‑Ahkam Allah, who was still an infant at the time and ascended to the throne under the continued regency of al‑Afdal (en.wikipedia.org).

This biography reflects only verified historical data. If you would like further detail or focus on any specific aspect of his life or reign, let me know and I can expand accordingly.