The question of the time of the Christianization of Rus' (the Old Rus' population) remains a many-faceted argument. From early times, Christianity, more correctly the "right teaching" (Orthodoxy), was one of the basic identifiers characteristics of Russian ethnicity. The ethnonym "Rusnak" (Rusniak), which later arose among the Rusins, was counter to the ethnonym "Polak" (Rusnak - Orthodox vs Polak - Catholic). The process of the adoption of Christianity by the ancestors of the Rusins can be divided into 3 epochs periods. The first - from the 1st to 8th C., when the Slavs, Antes and later the Ulich and Tivertsy tribes came in contact with the Ancient World North-West of the Black Sea Region. Most likely, during this period of time, there were limited numbers of christened people. The second epoch is tied to connected with the missionary activity (in the 2nd half of the 9th C.) by Cyril and Methodius in Great Moravia which included Carpatho-Rus'. The final epoch was the christianization initiated by Prince Vladimir of the population of the Carpatho-Dniestrovian Lands, which were a structural part of Old Rus'.