Al-Hasan al-Hajjam ibn Muhammad ibn al-Qasim
Al-Hasan ibn Muhammad ibn al-Qasim, known by the sobriquet al-Hajjam was the tenth Idrisid ruler that held only the capital of Fes and its environs.
Al-Qasim descended from a cadet branch of the Idrisid dynasty: his grandfather, al-Qasim, was a younger son of the dynasty's second ruler, Idris II. In 922 or 925 or 928 he rose in revolt against the Fatimid Caliphate's viceroy in Morocco, Musa ibn Abi'l-Afiya, and recovered control of Fes. Two years later, he defeated Ibn Abi'l-Afiya in combat, but was betrayed by Hamid ibn Hamdan, the governor he appointed over Fes, and imprisoned, while Fes was surrendered to Musa.
Ibn Abi'l-Afiya then fell out with Hamid ibn Hamdan and the Fatimids, launching a persecution of the Idrisids, before siding with the Fatimids' enemies, the Umayyad Caliphate of Córdoba in 931. A complicated struggle followed between the Hamid ibn Hamdun, the Idrisids, their rivals from the Abu Sahl family, Musa ibn Abi'l-Afiya, and the Fatimids under the general Maysur. Allied with the Fatimids against Ibn Abi'l-Afiya, Hasan's brother al-Qasim Jannun managed to establish an Idrisid emirate in the Rif Mountains in northern Morocco, before switching his allegiance to the Umayyads in 944.