 The first conflict between the Khazars and the Abbasids resulted from a diplomatic manoeuvre by the Caliph al @-@ Mansur ( r . 754 – 775 ) . Attempting to strengthen the Caliphate 's ties with the Khazars , in c . 760 he ordered his governor of Armenia , Yazid al @-@ Sulami , to marry a daughter of the khagan <unk> . The marriage indeed took place amidst much celebration , but she died in childbirth two years later , along with her infant child . The khagan suspected the Muslims of poisoning his daughter , and launched devastating raids south of the Caucasus in 762 – 764 : under the leadership of a Khwarezmian tarkhan named Ras , the Khazars devastated Albania , Armenia , and Iberia , where they captured Tiflis . Yazid himself managed to escape capture , but the Khazars returned north with thousands of captives and much booty . A few years later , however , in 780 , when the deposed Iberian ruler <unk> tried to induce the Khazars to campaign against the Abbasids and restore him to his throne , the khagan refused . This was probably the result of a brief period of anti @-@ Byzantine orientation in Khazar foreign policy , resulting from disputes between the two powers in the Crimea . During the same period , the Khazars helped Leon II of Abkhazia throw off Byzantine overlordship . 
