The Khazars of the Middle Ages have been the subject of many theories linking them in some way to the Jews and to biblical prophecy. Many of the theories involving the origin of Khazar Jews and their hypothetical diaspora are conspiratorial and promoted by radical groups to advance racist ideas.
What we know about the Khazars is this: the Khazars were of Turkish and Mongol descent and in medieval times lived in the western part of the Turkish Empire. In the late sixth century AD, the various tribes of the Khazars united and gained independence from the Turks. The Khazar Khanate (the area ruled by the Khazars) remained sovereign for about the next three hundred years. What makes the Khazars unique in European history is the conversion of their King Bulan to a form of Judaism, along with the Khazar ruling class, about AD 740. A Khazar Jew could be either an ethnic Khazar (of Turkish or Mongol blood) who became a proselyte to Judaism or an ethnic Jew who lived in Khazaria.
By the second half of the 8th century, the Khazar Empire had reached the peak of its power. The borders of Khazaria extended from the northern shore of the Black Sea (including Crimea) and the Dnieper River in the west, to the Aral Sea in the east. The Khazars were hemmed in by the Caucasus Mts. to the south and by the Rus and Bulgars to the north. The realm of the Khazars covered parts of modern-day Russia, Ukraine, Kazakhstan, and Uzbekistan. The capital of Khazaria was Itil, located near the mouth of the Volga River. The Khazar Empire was important in world history for keeping Arab invaders south of the Caucasus and thus preventing Islam from spreading further north into Europe. As Charles Martel kept the Muslims at bay in Western Europe, the Khazars repelled them from Eastern Europe.
The origin of the Khazars is shrouded in mystery, and some people have come up with their own ideas to account for the existence of Khazaria. One theory is that the Khazars are actually Jews—the ten “lost tribes ” of Israel somehow found their way to Eastern Europe, and that explains their later “conversion” to Rabbinic Judaism.
Another theory says just the opposite: the Khazars are Turks with no Jewish blood at all. After Khazaria fell, the Khazar converts to Judaism supposedly emigrated to Poland, Germany, and other parts of Europe where they maintained a nominal Jewish identity and became known as Jews. According to the theory, the Ashkenazi Jews have been wrongly identified as Semitic, when they are in reality Turkish. This theory is often propounded by those who themselves claim to be “true Jews,” such as those in the British Israelism camp, resulting in demands for Jews in Israel to give up their land (as Turks, they have no right to the land) and excusing anti-Semitism (which cannot truly exist, since the Khazar Jews are false Jews).
Neither of these theories has any basis in reality. No credible historical or genetic evidence exists to substantiate the theory that the Khazars were biological Hebrews or that modern Jews did not descend from Abraham. Another theory—that the influx of “Khazar Jews” into Israel in 1948 fulfilled the biblical prophecy of Gog and Magog (see Ezekiel 38–39)—sees the Israeli fight for independence as the Khazar seizure of the land of Israel from the Muslims. That theory is equally baseless.
The whole history of the Khazar Jews might never be known. But here is a likely scenario: some ethnic Jews lived in Khazaria (and many other places) during the Middle Ages. In or near 740, a Khazarian king converted to Judaism, for personal, practical, or political reasons, and he brought some of his subjects with him. When the power of Khazaria diminished and the empire fell, many Jews—both ethnic and proselytes—left that area and, settling in Jewish communities elsewhere, merged with the local population. Such intermarriage between ethnic Jews and Gentile proselytes does not mean that Jews of Khazaric background are any less Jewish than other Ashkenazi. The Bible records several instances of Gentiles being brought into Jewish culture: Rahab and Ruth being clear examples (see Matthew 1:5).