Battle of the Great Zāb River

…last Umayyad caliph, at the Battle of the Great Zab River (750) in Mesopotamia and to the proclamation of the first Abbasid caliph, Abū al-ʿAbbās al-Saffāḥ.

…744–750), was defeated at the Battle of the Great Zab River (750). Members of the Umayyad house were hunted down and killed, but one of the survivors, ʿAbd al-Raḥmān, escaped and established himself as a Muslim ruler in Spain (756), founding the dynasty of the Umayyads in Córdoba.