Abu al-Abbas as-Saffah, d. 754, 1st Abbasid caliph (749-54). Raised to the caliphate by the armed might of Abu Muslim, he took the reign name as-Saffah [shedder of blood]. Most of the Umayyad family was exterminated, and the reign was one of massacre and force. He was succeeded by his brother al-Mansur.