Abu Muslim, c.728-755, Persian leader of the Abbasid revolution. By political and religious agitation he raised (747) the black banners of the Abbasids against the ruling Umayyad family. In 749 he established Abu al-Abbas as-Saffah, the head of the Abbasid family, as caliph of Islam. Abu Muslim became governor of Khorasan, but the caliph al-Mansur feared his power and treacherously murdered him.