The Third Fitna, was a series of civil wars and uprisings against the Umayyad Caliphate. It began with a revolt against al-Walid II in 744, and lasted until 747, when Marwan II emerged as the victor. The war exacerbated internal tensions, especially the Qays–Yaman rivalry, and the temporary collapse of Umayyad authority opened the way for Pro-Alid, Kharijite and other anti-Umayyad revolts. The last and most successful of these was the Abbasid Revolution, which began in Khurasan in 747, and ended with the overthrow of the Umayyad Caliphate and the establishment of the Abbasid Caliphate in 750.