( Banu ’l-ʿAbbās ), the dynasty of the Caliphs from 132/750 to 656/1258. The dynasty takes its name from its ancestor, al-ʿAbbās b. ʿAbd al-Muṭṭalib b. Hās̲h̲im, the uncle of the Prophet.

The story of the origins and nature of the movement that overthrew the Umayyad Caliphate and established the ʿAbbāsid dynasty in its place was for long known only in the much-revised version put about when the dynasty had already attained power, and, with it, respectab…