Al-Dahhak ibn Qays al-Shaybani

Al-Ḍaḥḥāk ibn Qays al-Shaybānī was the leader of a widespread but unsuccessful Kharijite rebellion in Iraq against the Umayyad Caliph Marwan II from 745 until his death in battle in 746.

Crisis of the caliphate and the Kharijite revolt The deposition of al-Walid II in spring 744 began a turbulent period in the Umayyad Caliphate; his successor Yazid III died within a few months, and the ambitious governor of Armenia and Azerbaijan Marwan ibn Muhammad, rebelled against Yazid's designated successor, Ibrahim ibn al-Walid. Marwan succeeded in gaining control of Damascus and Syria, but elsewhere his authority ranged from theoretical to non-existent.

In Iraq, this turmoil spilled over in the form of a struggle between Yazid III's governor Abdallah ibn Umar ibn Abd al-Aziz and Marwan's appointee, al-Nadr ibn Sa'id al-Harashi. This conflict allowed the Kharijites, a Muslim sect which had originated in Mesopotamia, to rise up. This revolt was initially led by Sa'id ibn Bahdal, but he died soon of the plague, and was succeeded by Dahhak. Dahhak quickly assembled a sizeable army, and managed to defeat the two rival governors, who had joined forces, in April/May 745. In the aftermath of their defeat, al-Harashi returned to Marwan and Abdallah ibn Umar retreated to the fortress of Wasit, where he was soon besieged. In August however Ibn Umar gave himself up, and, in an unprecedented act for a member of the Umayyad dynasty and of the Prophet's own Quraysh tribe, did homage to Dahhak, who was neither and who had by now been declared caliph by his followers. The Kharijite rebellion persisted, under Abu Dulaf, for another year, but by the end of 747, Mesopotamia, Iraq and Persia had been secured by Marwan.