Different theories have been brought forward regarding the origin of Mountain Jews and the exact date of their settlement in the Caucasus. The commonly accepted theory views Mountain Jews as early medieval immigrants from Persia and possibly the Byzantine Empire forced out by Islamic conquests. They settled in Caucasian Albania, on the left bank of the Kura River and interacted with the Kypchak Kaganate of Khazaria, which lied to the north. It was through these early Jewish communities that the Khazars converted to Judaism making it their state religion.