Khazars

Kingdom founded by a group of Turkic tribes in the 6th century AD on the southeastern section of today's European Russia near the Caspian Sea and the Caucasus?. Their first significant appearance in history is their aid to the campaign of the Byzantine emperor Heraclius against the Persians. During the 7th and 8th centuries they fought a series of wars against the Islamic Arab Empire. Although they stopped the Arab expansion into Eastern Europe for some time after these wars, they were forced to withdraw behind the Caucasus, as well. Afterwards they extended their territories from the Caspian Sea in the east to the north of Black Sea in the west. Interestingly, the Khazar royalty and nobility adopted Judaism, though the majority of the population continued to follow paganism. In the 10th century the empire began to decline due to the attacks of the Russian and other Turkic tribes and their political significance greatly diminished toward the ends of the 12th century.

Some modern anti-Semites claim that the Jews of today are not really Judeans at all, but rather descendants of the Khazars alone; historians however reject this claim.