nephew of the first two Abbassid Caliphs, as-Saffah and al-Mansur
725 CE
to 784 CE
'Isa ibn Musa ibn Muhammad ibn Ali ibn Abdallah ibn al-Abbas (died 783/4) is a nephew of the first two Abbassid Caliphs, as-Saffah (r. 750–754) and al-Mansur (r. 754–775), and for a long time heir-apparent of the Caliphate, until he is superseded by al-Mansur's son al-Mahdi (r. 775–785).