In the nineteenth-century South Caucasus, hundreds of local farmers and nomads petitioned Russian authorities to allow them to become Christians. Most of them were Muslims and specifically requested to join the Armenian Apostolic Church. This article explores religious conversions to Armenian Christianity on Russia's mountainous southern border with the Ottoman Empire and Iran. It demonstrates that tsarist reforms, chiefly the peasant reform and the sedentarization of nomads, accelerated labor migration within the region, bringing many Muslims, Yazidis, and Assyrians into an Armenian environment. Local anxieties over Russian colonialism further encouraged conversions. I argue that by converting to Armenian Christianity many rural South Caucasians benefited from a change in their legal status, which came with the right to move residence, access to agricultural land, and other freedoms. Russia's Jewish communities, on the other hand, saw conversion to Armenian Christianity as a legal means to circumvent discrimination and obtain the right to live outside of the Pale of Settlement. By drawing on converts’ petitions and officials’ decisions, this article illustrates that the Russian government emerged as an ultimate arbiter of religious conversions, evaluating the sincerity of petitioners’ faith and how Armenian they had become, while preserving the empire's religious and social hierarchies.