The Mountain Jews (Juhuro, from Judeo-Tat for ‘Jew’) are an ancient Jewish community of the eastern Caucasus — primarily in Dagestan and Azerbaijan — who speak Judeo-Tat, a Jewish dialect of a Northwestern Iranian language. Their origins predate the Khazar empire: they are likely descendants of Persian Jewish communities who migrated to the Caucasus during the Parthian and Sassanid periods (2nd century BC – 7th century AD). The Khazar conversion to Judaism in ~740 AD overlapped geographically with these communities and may have reinforced their numbers or strengthened trade and cultural ties. The Mountain Jews maintained their distinctive Jewish identity through Russian imperial rule and Soviet atheist persecution — Stalin suppressed Jewish religious life across the USSR but Mountain Jews preserved community cohesion in remote Caucasus villages. Today approximately 100,000–150,000 Mountain Jews exist, with large communities in Israel (where they have been immigrating since the 1970s), New York, and Moscow. In Israel they form a distinct Mizrahi community maintaining Judeo-Tat language and customs.