Abu Muslim al-Khurasani publicly begins the Abbasid uprising in Khurasan under the movement’s black banners, turning years of clandestine propaganda into open rebellion against Umayyad rule.
Rebel forces take control of Merv, forcing Umayyad governor Nasr ibn Sayyar out and enabling Abbasid armies to push westward from a secure base in Khurasan.
Nasr ibn Sayyar, the last Umayyad governor of Khurasan and a key figure resisting the revolt, dies while retreating westward—further weakening Umayyad control in the east.
Abbasid forces under Qahtaba ibn Shabib defeat a major Umayyad army near Isfahan, a key step in carrying the revolution from Iran toward Iraq.
Ibrahim al-Imam, head of the Abbasid family and the clandestine movement, dies after being imprisoned by Umayyad authorities; leadership shifts to his brothers, including Abu al-Abbas.
Abbasid forces besiege the Umayyad garrison at Wasit, the last major Umayyad stronghold in Iraq; the long siege ties down Umayyad defenders as the decisive campaign unfolds elsewhere.
During the push into Iraq, Qahtaba ibn Shabib is killed, but command passes to his son al-Hasan, who takes Kufa—positioning the Abbasid leadership to emerge openly.
In Kufa, Abu al-Abbas (al-Saffah) is proclaimed caliph in Rabiʿ I 132 AH (October 749), giving the revolution a declared dynastic and governmental center in Iraq.
At the Battle of the Great Zab, Abbasid forces rout the army of Caliph Marwan II, a decisive military blow that effectively ends Umayyad rule in the central caliphate lands.
Following an 11-month siege, Wasit capitulates to the Abbasids, removing the final major Umayyad military foothold in Iraq and consolidating the new regime’s control of the heartland.
After fleeing Syria and continuing his retreat, the last Umayyad caliph Marwan II is caught and killed in Egypt, marking the collapse of Umayyad political authority in the east.
Al-Saffah establishes Anbar as his capital (with additional construction for Khurasani troops nearby), reflecting a shift away from volatile Kufa while the dynasty’s institutions take shape.
Al-Saffah dies after a short reign, and his brother Abu Jaʿfar al-Mansur becomes caliph—an accession widely associated with the durable consolidation of Abbasid rule.
Al-Mansur begins building the Round City of Baghdad as a new imperial capital, signaling a decisive administrative and political re-centering of the caliphate from earlier Iraqi bases.
Founding of the Abbasid Caliphate and the Revolution (747–762)
