The rebellion of 852 in Armīniya (Abbasid province in the Caucasus) resulted in the assassination of the governor of the Abbasid Caliphate. Caliph al-Mutawwakil (r. 847-861) dispatched a punitive expedition with intention of conquering and subduing the areas that were out of Abbasid control. Bughā al-Kabir was appointed in command of the Abbasid army and was sent to the Caucasus in the same year. Bughā's Caucasian military campaign was of large scale, arguably the largest Caucasian military expedition organized by the Caliphate in the 9th century. The Abbasid army attacked, imprisoned, and killed the population of Armīniya involved in the assassination of the Abbasid governor; Muslim usurpers who were unwilling to yield the orders of the Caliphate got punished; the governor of Tbilisi Isḥāq b. Ismāʿīl was captured and beheaded while his residence and the center of Muslim position in Kartli, Tbilisi, was submitted. A large number of Christian Armenian and Arranian (Albanian) rulers were imprisoned. The Georgian rulers, who ruled the northern outskirts of the Caliphate, were divided. They mostly opposed the Abbasids, while some of them supported the Caliph. The 853- 854 campaigns were successful for Bughā and his Georgian allies, but other Georgian rulers asked for support from the Byzantines and the Khazars. According to al-Yaʿqūbī (the 9th c.), the Caucasian rulers who had escaped captivity called for the help of Khazars, Byzantines, and Slavs in the fight against the Abbasids. They received a positive response. A large force under Khazar leadership was sent against the Caliphate while the Byzantines launched an attack on the Eastern Mediterranean domains of the Caliphate. In 855, in the course of Khazar-Byzantine-Slav involvement in the Caucasian affairs, the Abbasids adopted a defensive stance. Derbent was successfully protected. The Khazars and their allies were unable to penetrate in the direction of Arran. In the direction of Kartli, the Khazars were more successful, probably with the support of local rulers.