SUMMARY
The article analyses the content of the chronicle of known Protestant leader of the Polish-Lithuanian Commonwealth Andrzej Wengierski “The Slavic Reformation”, which was published in Amsterdam in 1679. The author of the article believes that in his understanding of the essence and historical logic of the Reformation Andrzej Wengierski proceeded the church-historical concept proposed by the publishing collective of the Magdeburg Centuries. At the same time, the unconditional innovation of the Polish chronicler was the desire to show the specifics of the Reformation in Eastern Europe, in particular in the region of the Catholic-Orthodox borderland. Andrzej Hungarian had special attention to the Cyrillo-Methodian Tradition of the Slavic peoples, which had in itself an ecumenical potential. According to the chronicler this Tradition, as well as common political and inter-church interests, contributed to the convergence of the Orthodox in the Kyivan Church of with the Protestants. Andrzej Wengierski covered the events of church life in the Polish-Lithuanian Commonwealth in the context of its important political and cultural processes, showing its influence on the social and cultural life of Ruthenia. The author of the article analyzed the chronicle of Andrzej Wengerski in the context of comprehension the phenomenon of the Reformation and various models of church reforms in Western and Eastern Europe, as well as in the Kyivan Metropolis in the 16th-17th centuries.