Ibrahim ibn Musa al-Kazim

Ibrahim ibn Musa al-Kazim (Arabic: إبراهيم بن موسى الكاظم‎‎), known as al-Jazzar (Arabic: الجزار‎‎, "the Butcher"), was a ninth century Alid leader who led a rebellion against the Abbasid Caliphate in the Yemen in the aftermath of the Fourth Fitna. He later seized control of Mecca in ca. 817, and was subsequently recognized as legal governor of the city by the caliph al-Ma'mun.

An Alid by birth, Ibrahim was one of the eighteen or nineteen sons of the seventh Shi'ite imam Musa al-Kazim (d. 799), and a great-great-great-great-grandson of 'Ali ibn Abi Talib. He was a brother of the eighth imam 'Ali ibn Musa al-Rida (d. 818), who was briefly the designated heir of the Abbasid caliph al-Ma'mun (r. 813–833).

Ibrahim became active as a rebel following the damaging civil war of 811–813 between the rival caliphs al-Amin and al-Ma'mun, which had greatly weakened the ability of the Abbasid government to maintain its authority in Baghdad and the provinces of the empire. While in Mecca in 815, he was appointed by Abu al-Saraya al-Sari ibn Mansur, who had launched a pro-Alid revolt in southern Iraq and seized the cities of al-Kufah, al-Basrah, Mecca, and Medina, to conquer the Yemen on his behalf, and he accordingly marched south toward the province with a large force. Upon learning of his advance, the governor of the Yemen, Ishaq ibn Musa ibn 'Isa al-Hashimi, decided against putting up any resistance and instead withdrew with his troops for the Hijaz, in effect surrendering the province to Ibrahim. The latter was consequently able to enter the Yemen without facing any significant resistance, and he proceeded to occupy Sana'a in September 815 and take control of the country.

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