The Abbasid Caliphate or Abbasid Empire was the third Islamic caliphate, founded by a descendant of Muhammad's uncle, Abbas ibn Abd al-Muttalib, from whom the Abbasid dynasty derives its name. The preceding Umayyad Caliphate was overthrown by the Abbasid Revolution in 750 CE (132 AH), after which the Abbasids ruled as caliphs from their base in Iraq, with Baghdad as their capital for most of their history.