The Arab–Khazar wars were a series of conflicts fought between the armies of the Khazar Khaganate and the Rashidun, Umayyad, and Abbasid caliphates and their respective vassals. Historians usually distinguish two major periods of conflict, the First Arab–Khazar War (c. 642–652) and Second Arab–Khazar War (c. 722–737), but the Arab–Khazar military confrontation also involved sporadic raids and isolated clashes from the middle of the 7th century to the end of the 8th century.