At about the same time as Karaism sprang into existence, an event occurred which only slightly affected the development of Jewish history, but which roused the spirits of the scattered race and restored their courage. The heathen king of a barbarian people, living in the north, together with all his court, adopted the Jewish religion. The Chazars, or Khozars, a nation of Finnish origin, related to the Bulgars, Avars, Ugurs or Hungarians, had settled, after the dissolution of the empire of the Huns, on the frontier between Europe and Asia. They had founded a kingdom on the Volga (which they called the Itil or Atel) at the place near which it runs into the Caspian Sea, in the neighborhood of Astrakhan, now the home of the Kalmucks. Their kings, who bore the title of Chakan or Chagan, had led these warlike sons of the steppe from victory to victory. The Chazars inspired the Persians with so great a dread that Chosroes, one of their kings, found no other way of protecting his dominions against their violent invasions than by building a strong wall which blocked up the passes between the Caucasus and the sea. But this "gate of gates" (Bab al abwab, near Derbend) did not long serve as a barrier against the warlike courage of the Chazars. After the fall of the Persian empire, they crossed the Caucasus, invaded Armenia, and conquered the Crimean peninsula, which bore the name Chazaria for some time. The Byzantine emperors trembled at the name of the Chazars, flattered them, and paid them a tribute, in order to restrain their lust after the booty of Constantinople. The Bulgarians, and other tribes, were the vassals of the Chazars, and the people of Kiev (Russians) on the Dnieper were obliged to pay them as an annual tax a sword and a fine skin for every household. With the Arabs, whose near neighbors they gradually became, they carried on terrible wars. Like their neighbors, the Bulgarians and the Russians, the Chazars professed a coarse religion, which was combined with sensuality and lewdness. The Chazars became acquainted with Islam and Christianity through the Arabs and Greeks, who came to the capital, Balanyiar, on matters of business, in order to exchange the products of their countries for fine furs. There were also Jews in the land of the Chazars; they were some of the fugitives that had escaped (723) from the mania for conversion which possessed the Byzantine Emperor Leo. It was through these Greek Jews that the Chazars became acquainted with Judaism. As interpreters or merchants, physicians or counselors, the Jews were known and beloved by the Chazar court, and they inspired the warlike king Bulan with a love of Judaism.