The Abbasid Revolution refers to the overthrow of the Umayyad Caliphate (661–750 CE), the second of the four major Caliphates in early Islamic history, by the third, the Abbasid Caliphate (750–1258 CE). Coming to power three decades after the death of the Muslim prophet Muhammad and immediately after the Rashidun Caliphate, the Umayyads were a feudal Arab empire ruling over a population which was overwhelmingly non-Arab as well as primarily non-Muslim. Non-Arabs were treated as second-class citizens regardless of whether or not they converted to Islam, and this discontent cutting across faiths and ethnicities ultimately led to the Umayyads' overthrow. The Abbasid family claimed to have descended from al-Abbas, an uncle of the Prophet.
The revolution essentially marked the end of the Arab empire and the beginning of a more inclusive, multiethnic state in the Middle East. Remembered as one of the most well-organized revolutions during its period in history, it reoriented the focus of the Muslim world to the east.
By the 740s, the Umayyad Empire found itself in critical condition. A dispute over succession in 744 led to the Third Muslim Civil War, which raged across the Middle East for two years. The very next year, al-Dahhak ibn Qays al-Shaybani initiated a Kharijite rebellion that would continue until 746. Concurrent with this, a rebellion broke out in reaction to Marwan II's decision to move the capital from Damascus to Harran, resulting in the destruction of Homs – also in 746. It was not until 747 that Marwan II was able to pacify the provinces; the Abbasid Revolution began within months.