The article is a summary of the monograph by N. ‘Christianity among Chuvash of the Middle Volga Region in the Sixteenthth-Eighteenth Centuries: A Historical Essay’ (Kazan, 1912), which he defended as his Master thesis at the Kazan Spiritual Academy. This work drew criticism of missionaries, since, from their point of view, the activities of missionaries in the sixteenth – eighteenth centuries was portrayed by the author in a limited way and in a rather critical manner. But N. did not idealize the Chuvash people either, arguing that practical considerations plaid the main role in their conversion to Christianity, as well as the hardening of the state policy towards non-Christians. A scrupulous knowledge of the subject allowed the author to show various aspects of Christianization, and factors that contributed to Christianization (an increasing number of mixed marriages, Russification of Chuvash), as well as the reasons that made that Christianization formal (family customs, observance of traditional rituals, etc.). The article also quite clearly depicts folk syncretic rituals and practices that emerged as a result of the interaction of Christian and traditional Chuvash religious beliefs and ritual practices.