The Khazars, having been compelled to shift the center of their empire northward after 737, establish their capital at Itil (located near the mouth of the Volga River) and accept the Caucasus Mountains as their southern boundary.

During the same period, however, they expand westward.

The most striking characteristic of the Khazars is the apparent adoption of Judaism by the khagan—a secluded supreme ruler of semireligious character—and the greater part of the ruling class in about 740.

The circumstances of the conversion remain obscure, the depth of their adoption of Judaism difficult to assess; but the fact itself is undisputed and unparalleled in central Eurasian history.

A few scholars have asserted that the Judaized Khazars are the remote ancestors of many eastern European and Russian Jews, later known as Ashkenazim.

Whatever the case may be, religious tolerance is practiced in the Khazar empire, and paganism continues to flourish among the population.

Russian archaeologists will announce in 1999  that they had successfully reconstructed a Khazarian vessel from the Don River region, revealing four inscriptions of the word “Israel” in Hebrew lettering.

It is today the accepted opinion among most scholars in the field that the conversion of the Khazars to Judaism was widespread, and not limited merely to the royal house and nobility.

According to tenth-century Khazar King Joseph, in his Reply to Hasdai ibn-Shaprut (c. 955): “After those days there arose from the sons of [khagan] Bulan's sons a king, Obadiah by name.

He was an upright and just man.

He reorganized the kingdom and established the Jewish religion properly and correctly.

He built synagogues and schools, brought in many Israelite sages, honored them with silver and gold, and they explained to him the 24 Books of the Bible, Mishnah, Talmud, and the order of prayers established by the Khazzans.

He was a man who feared God and loved the law and the commandments.”