Battle of Marj Ardabil

The battle was one of the heaviest Arab defeats of the Second Arab–Khazar War, fought since the early 720s for control of the South Caucasus. Al-Jarrah, reappointed governor of Armenia and Adharbayjan in 729, had campaigned north of the mountains, but in 730 a great Khazar army invaded the South Caucasus — led, according to the Arabic sources, by Barjik, a son of the khagan, while the Armenian chronicler Łewond names Tar'mach. Al-Jarrah withdrew to Ardabil, the capital of Adharbayjan, where most of the Muslim settlers, about 30,000 with their families, lived, and chose to give battle on the plain instead of holding a defensive position until reinforcements came.

The fighting lasted three days, from 7 to 9 December 730 by the usual reckoning (6–8 December in some accounts). On the second evening many of the levies fled; on the third day the Khazars overwhelmed the rest, and al-Jarrah fell. Of his army, put at 25,000 men, only a few hundred are said to have escaped; the figure of 300,000 Khazars given by Arab writers is regarded as greatly exaggerated. Ardabil was taken and sacked — the chronicler Agapius speaks of up to 40,000 captives from the city, the army and the countryside — and Khazar detachments plundered Adharbayjan and reached Mosul, next to the Umayyad heartlands.

News of the defeat spread as far as Byzantium. Caliph Hisham sent the veteran Sa'id ibn Amr al-Harashi, who defeated the scattered Khazar raiding parties one by one and freed thousands of Muslim captives, and then his half-brother Maslama, who recovered Derbent. In 737 Marwan ibn Muhammad, the future caliph Marwan II, led a great expedition to the Khazar capital on the lower Volga, after which large-scale war ceased; the peace was broken by Khazar invasions in 762–764, when they took Tiflis, and in 799.