Abbasid Revolution

The Abbasid revolution was the uprising of 747–750 that overthrew the Umayyad Caliphate and brought the Abbasid dynasty to power. Launched in the eastern province of Khorasan by the revolutionary leader Abu Muslim under black banners, it swept west across Iran into Iraq and Syria in about three years. The new Abbasid Caliphate moved the centre of the Islamic world eastwards and later built its capital at Baghdad.

By the 740s the Umayyad state, ruled from Syria, was in deep crisis. A disputed succession in 744 led to a civil war, the Third Fitna, followed by a Kharijite rebellion and revolts against Caliph Marwan II, who moved his capital from Damascus to Harran. Many groups resented Umayyad rule. Supporters of the family of the Prophet Muhammad, especially the followers of his cousin Ali, remembered the killing of Ali's son Husayn at the Battle of Karbala in 680. Non-Arab converts to Islam often complained of being treated as second-class Muslims, and many Arabs also opposed the dynasty's central authority.

From around 719, missionaries of a movement called the Hashimiyya worked quietly in Khorasan, a vast frontier region in what is now north-eastern Iran and Central Asia. They called for rule by an unnamed member of the Prophet's family who would be acceptable to all, without openly naming the Abbasids, descendants of Muhammad's uncle al-Abbas. In about 746 Abu Muslim, whose origins are disputed in the sources, took charge of the movement in Khorasan. Its forces drew heavily on Arab tribesmen long settled in the province, alongside Iranian and other non-Arab converts.

In June 747 Abu Muslim raised the black banners in the villages around Merv, and in February 748 he took the city itself, driving out the Umayyad governor Nasr ibn Sayyar. His general Qahtaba ibn Shabib led an army westwards, defeating Umayyad forces at Gorgan and Isfahan and besieging Nahavand, which surrendered after more than two months. By 749 Umayyad rule in Iran was at an end.

The Abbasid army crossed into Iraq in 749. Qahtaba was killed in a night attack on the Umayyad army, but the Umayyad commander Ibn Hubayra was beaten and shut himself up in Wasit, while Abbasid forces entered Kufa in September. Marwan II had the Abbasid leader Ibrahim al-Imam put to death, and on 28 November 749 al-Saffah, described in the sources as a great-grandson of al-Abbas, was proclaimed caliph in the mosque at Kufa. Some in the movement, it is reported, had hoped for a descendant of Ali instead.

In January 750 an Abbasid army under al-Saffah's uncle Abd Allah ibn Ali met Marwan II near the Great Zab river in northern Iraq. The Battle of the Zab destroyed the caliph's army; one modern estimate puts the Umayyad force at 100,000 to 150,000 against 10,000 to 30,000 Abbasid troops, though such figures are uncertain. Damascus fell in April, and in August Marwan was tracked down and killed in Egypt. Most surviving members of the Umayyad family were hunted down; according to the sources, about eighty who gathered at Jaffa after a promise of amnesty were massacred.

The new rulers soon turned on their allies. The second Abbasid caliph, al-Mansur, had Abu Muslim executed in 755, and the hopes of Ali's supporters were disappointed. Al-Mansur founded Baghdad in 762. Non-Muslims regained government posts they had lost under the Umayyads, though the caliph remained an Arab and Arabic remained the language of administration. One Umayyad prince, Abd al-Rahman, escaped to al-Andalus, where his family ruled from Córdoba until 1031. The Abbasids ruled from Baghdad until the Mongol siege of Baghdad in 1258.

Our 700 map shows the Umayyad Caliphate at its height, and the 800 map shows the Abbasid Caliphate that replaced it.