5. Caliphate - Abbasid, Islamic Empire, Sunni | Britannica
Link: https://www.britannica.com/place/Caliphate/The-Abbasid-caliphate
Description: WebCaliphate - Abbasid, Islamic Empire, Sunni: The Abbasids, descendants of an uncle of Muhammad, owed the success of their revolt in large part to their appeal to various pietistic, extremist, or …