ENThe Grand Duchy of Lithuania was a multi-ethnic and multi-confessional state. Various religious groups (both Christian and non-Christian) coexisted quite peacefully and enjoyed freedom of religion. The aim of the article is to explore the social conditions that made it possible to ensure religious peace in the Grand Duchy of Lithuania and the Polish–Lithuanian Commonwealth at large. The study is based on three conflicts that arose in Polatsk Voivodeship between representatives of different Christian denominations at the end of the sixteenth century: a conflict between Orthodox and Catholic burghers of Polatsk because of the introduction of a new (Gregorian) calendar, a land conflict over the ownership of two villages between the Polatsk Jesuit college and the Polatsk Orthodox archbishop, and a conflict over the right of fishing in Lake Ulichy between local gentry and the Jesuits. The analysis of the cases shows that it was the political nation’s value system and political system of the Grand Duchy of Lithuania (as well as the Polish Kingdom) that guaranteed freedom of religion to various religious groups and enabled their peaceful coexistence for a long time. The central points of the value system were the concepts of “concord,” “peace,” “love,” “law,” and “custom.” In its turn, it promoted the internal stability in the Polish–Lithuanian Commonwealth. The situation changed at the turn of the sixteenth and seventeenth centuries. Since the late sixteenth century, the royal authority had been rendering priority support exclusively to the Catholic Church, especially to the Society of Jesus. Such policy undermined the basis of religious tolerance in the Commonwealth. Nevertheless, I should emphasize that in the late sixteenth and early seventeenth centuries, the overwhelming majority of inter-confessional conflicts in the Grand Duchy of Lithuania had been still resolved legally, without the use of force. [Publisher annotation]