 Relations between the two powers remained relatively quiet until the early years of the 8th century , by which time the stage for a new round of conflict was set : by this time , Byzantine political authority had been marginalized in the Caucasus , and the Caliphate tightened its grip on Armenia after the suppression of a large @-@ scale rebellion in 705 . With Armenia annexed into the Caliphate , the Arabs and the Khazars faced each other for control of the Caucasus . Only the western parts of Transcaucasia , comprising modern Georgia , remained free from direct control by either of the two rival powers . War broke out in 713 / 714 , when the Umayyad general Maslama , a son of the Caliph Abd al @-@ Malik ( r . 685 – 705 ) , conquered Derbent . Maslama then drove deeper into Khazar territory , trying , without success , to subdue the Huns living north of the Caucasus ( who were Khazar vassals ) . The Khazars opposed him under the general Alp ' , but also launched raids to the south into Albania in response . In 717 , the Khazars raided in force into Adharbayjan , but they were driven back by the Arabs under Hatin ibn al @-@ Nu 'man . 
