ENThe article is divided into an introduction, three subchapters, and a conclusion. The introduction explains the purposes of the study, and the terminology used as well as presents the source basis. In the first subchapter, a genesis of the Reformation in Podlasie Region is outlined, with a role played by Mikołaj "The Black" Radziwiłł. Next, a list of Protestant churches is presented in the district of Podlasie existing in 1560-1796, together with the vicissitudes of the Protestants under the protection of the Radziwiłłs. The study closes with a conclusion containing the answers to the research questions posed in the introduction.