EN
The autor of this study is concerned with the occupation of a part of the northwestern Kingdom of Hungary by Bolesław I the Brave at the beginning of the 11th century. He analyses the military campaigns of the Polish prince in medieval narrative sources and annals. The author tries to find out why Bolesław I the Brave occupied part of the Kingdom of Hungary, what was the territory and who ruled there in the early third of the 11th century.