Historically Judaism has been represented by the mountain Jews. Movses Kalankatvasi refers to the arrival of mountain Jews in the Caucasus to the 1st century B.C, while researchers have different views upon this issue.
According to one source, mountain Jews that are the most ancient Jewish communities were generated from the people of Israel, driven away from Palestine by the shahs of Assyria and Babylon, and settled in Midia. Their ancestors were the first to establish Judaism, which resided apart from Palestine. They did not participate in the persecutions of Jesus Christ at the beginning of their formation as a single community. In Midia they formed mixed communities with tats. Thus, mountain Jews spoke the language of tats, which is the ancient dialect of the Persian language comprising Aramaic and Jewish words.
Other researchers consider that mountain Jews were moved to the East Caucasus by Sassanid ruler Khosrow Anoushiravan (531-574). The ruler built towers in the Caucasus and settled Persians and Jews that he removed from Mesopotamia to these cities. The Tat language spoken by mountain Jews also survived since that period. At least it is known that mountain Jews who came to Azerbaijan fifteen centuries ago due to the policy of Sassanid were settled in the borderline districts to ensure the country’s security. Although they had close relations with local inhabitants, they preserved their religion, traditions, lifestyle, and way of thinking.