Khazars

"The semi-nomadic Turkic Khaganate of the Khazars that dominated the Pontic Steppe between the Dnieper and the Ural rivers and the Northern Caucasus from the seventh to the late tenth century ruled a conglomerate of various peoples (Slavs, Alans, Bulghars, Finno-Ugrians, and Turks). By the 680s, with the collapse of the West Turkic Empire, they overran the old Great Bulghar state and entered into an alliance with the Byzantines against the Sassanid Empire and the Arabs. First they led marauding invasions against Georgia and Armenia: then, with the upper strata adopting Judaism, they consolidated their state, and built a large commercial network. They were able to withstand both the Arab expansion in the Caucasus and any Asian warriors attacking the Volga frontier until the late ninth century, when they were finally overwhelmed and absorbed by the Rus, the Patzinaks (Pechenegs), and the Oghuz." Rogers, C., The Oxford Encyclopedia of Medieval Warfare and Military Technology, Volume 1