Second Arab–Khazar War: from Balanjar to Marwan’s campaign to the Volga

After decades of raids the conflict flared into full-scale war in the winter of 721/722, when a Khazar army invaded Armenia and routed its Arab governor. Caliph Yazid II sent al-Jarrah ibn Abdallah with Syrian troops; he entered Derbent, the fortress guarding the Caspian Gates, defeated the Khazars north of it and on 21 August 722 stormed Balanjar, which the Khazars had tried to defend with a ring of wagons tied together. The nomads, however, did not depend on towns: they fell back and struck again south of the mountains. Al-Jarrah and Maslama, a half-brother of Caliph Hisham, took turns in command, advancing through Derbent and the Darial Pass, until in 730 a great Khazar army outflanked the Arabs and destroyed al-Jarrah’s forces at Ardabil in Adharbayjan (north-western Iran): al-Jarrah was killed, the city was sacked, and Khazar detachments reached Mosul. The defeat shocked the caliphate. Sa'id al-Harashi defeated the scattered Khazar bands, and Maslama retook Derbent and made it an Arab military colony with a garrison of Syrian troops.

In 732 Hisham gave the command to Marwan ibn Muhammad, the future last Umayyad caliph. After campaigns in Armenia, Georgia and Alania, in 737 he invaded Khazaria with the largest army ever sent against it: one column moved along the Caspian from Derbent, the main force crossed the Darial Pass. The Arabs joined forces at Samandar and pressed on to the Volga, where Arab sources place the khagan’s capital, al-Bayda; the khagan withdrew, and a detachment sent across the river routed a Khazar army and killed its commander. The khagan then asked for peace and, by the Arab accounts, agreed to become a Muslim; Marwan carried off many Khazar and Slav captives and settled them in the Caucasus. Modern historians doubt that the conversion meant much: al-Baladhuri’s version suggests that only a minor Khazar lord accepted Islam, and the Khazar ruling house later adopted Judaism.

The frontier settled at Derbent, which remained the northern outpost of the Islamic world, while the Khazars kept the North Caucasus and the steppe; the war never again reached such a scale, although the Khazars raided the South Caucasus in the 760s and in 799. Douglas Dunlop compared the Khazars with the Franks, who stopped the Arabs at Poitiers at about the same time, and Mikhail Artamonov and Peter Golden likewise saw in them the power that halted the Arab advance; Khalid Blankinship counts the drain of the Caucasus war on the Syrian army among the causes of the Umayyads’ fall. The archaeologists Murad Magomedov and Svetlana Pletnyova linked the rise of the Saltovo-Mayaki culture on the Don with Alans whom the Khazars resettled there from the North Caucasus because of the war.