When al-Saffāḥ died, the people of Damascus pledged allegiance to him for the caliphate, and he summoned his uncle to acknowledge his claim.

During Hāshim’s brief rule the man who actually administered affairs on his behalf was the commander ʿUthmān ibn ʿAbd al-Aʿlā ibn Surāqah al-Azdī. When Ṣāliḥ, the uncle of al-Manṣūr, advanced to fight him, both Hāshim and Ibn Surāqah fled.

Ibn Surāqah had publicly reviled the Abbasids from the pulpit in Damascus because of their deeds and their blood-shed. He had originally been appointed over Damascus by ʿAbd Allāh ibn ʿAlī, but after insulting them he was dismissed, and Muqātil ibn Ḥakīm was sent in his place. Muqātil succeeded in capturing Ibn Surāqah and beheaded him. We have no information about what became of Hāshim. Ibn ʿAsākir relates the story.

75 – ʿAbd Allāh ibn ʿAlī ibn ʿAbd Allāh ibn al-ʿAbbās *

He was the uncle of al-Saffāḥ and al-Manṣūr, one of the notable men of his age and among Quraysh’s shrewdest strategists. He was a champion, courageous, awe-inspiring, imperious, harsh, and prodigal in blood-shed. Through him the Abbasid state was established.

Leading forty thousand men—or more—he engaged the caliph Marwān near Mosul, routed him, scattered his forces, pursued him relentlessly, and crossed the provinces until he reached the royal seat, Damascus. He besieged it for several days, stormed it by the sword, and up to midday slew some fifty thousand Muslims, soldiers and civilians alike, sparing neither covenant nor kinship nor lineage.

He then at once dispatched his brother Dāwūd ibn ʿAlī to pursue Marwān. Dāwūd overtook him at the village of Busir in Egypt, attacked him by night, and Marwān fought on until he was killed; his two sons fled to Abyssinia, and the Umayyad dynasty came to an end.

When al-Saffāḥ died, ʿAbd Allāh claimed that he was his designated heir. The governors of Syria swore allegiance to him, and he received the pledge of allegiance.