al-Sharif al-Murtada

Abu al-Qasim 'Ali ibn al-Husayn, known as al-Sharif al-Murtada and by the honorific title 'Alam al-Huda ("Banner of Guidance"), was a leading Twelver (Imami) Shi'i scholar of Buyid-era Baghdad. He was born there in 355 AH (965 CE) into a distinguished family of descendants of the Prophet; his younger brother was the poet al-Sharif al-Radi (born 359 AH/970 CE), traditionally credited with compiling the Nahj al-Balagha. He studied under the theologian al-Shaykh al-Mufid and, after his teacher's death, became a central authority for Imami communities, fielding written questions from as far as Aleppo, Mosul, and the Levantine coast.

He held the office of naqib al-ashraf, the recognized head of the Prophet's descendants in Iraq (an appointment of the Buyid and Abbasid authorities). As a thinker he is remembered for developing a strongly rationalist Imami kalam (speculative theology) and usul al-fiqh (legal theory); historians note his affinities with the Mu'tazila, a rationalist theological school, partly transmitted through the Mu'tazili judge 'Abd al-Jabbar, under whom he studied. His major works include al-Shafi fi al-imama (a defense of the Imamate), the legal-theory treatise al-Dhari'a, and Tanzih al-anbiya'. His most famous student was al-Shaykh al-Tusi.

He died in Baghdad in 436 AH (1044 CE). Where he is buried is disputed in the tradition: some reports place his grave at Karbala near the shrine of Imam al-Husayn, others at Kazimayn.