Sons of Umayya or Umayyads Arabic. Al-Umawiyyūn were the ruling family of the Caliphate between 661 and 750 and later of Al-Andalus between 756 and 1031. Abbasid Caliphate Middle East Map Middle Eastern History Al-Mansur was the second Abbasid Caliph reigning from 136 AH to 158 AH 754775 and succeeding his brother al-Saffah. . Al-Mansur is generally regarded as the greatest Caliph of. In the pre-Islamic period they were a prominent clan of the Meccan tribe of Quraysh descended from Umayya ibn Abd. The Umayyad dynasty Arabic. Abbasid Caliphate As-Saffah was the first caliph of the Abbasid caliphate one of the longest and most important caliphates Islamic dynasties in Islamic history.