The presented diploma thesis deals with the church policy of the Bohemian King John of Bohemia in relation to Upper Lusatia and the Duchy of Wrocław. The areas which thanks to John's successful territorial policy have become an integral part of the Bohemian Kingdom for several centuries. As the named countries belonged to the indivisible dominions of the Bohemian ruler, he was able to fully develop there his donor activities. The research is based on an analysis of available sources especially of a diplomatic nature and is also focused on narrative sources. The aim of this work is to analyse and interpret John's relationship to church institutions especially chapters and monasteries in defined regions. Attention is also paid to the ecclesiastical patronage of Henry of Jawor a longtime competitor of John of Bohemia in the struggle for Upper Lusatia, who ruled over Görlitz until 1329 and over part of Upper Lusatia until the end of his life († 1346). The work would like to contribute to the evaluation of John's support for church institutions, which was aimed at strengthening his position in these areas. Keywords: John of Bohemia; Henry of Jawor; Upper Lusatia; Silesia; Duchy of Wrocław; church policy; donation; confirmation