EN
The author of this study tries to determine the years, when Bolesław I the Brave occupied a part of the northwestern Kingdom of Hungary and when Stephen I of Hungary regained this part. He rejects the previous opinions of historians, who dated this event from the year 1000 / 1003 to the year 1025 / 1029 / 1030 / 1031. According to the author the military campaign of the Polish prince to the Kingdom of Hungary took place in the first third of the 11th century during Polish-German wars. Bolesław I the Brave lost a part of the northwestern Kingdom of Hungary in the final phase of Polish-German wars.