Boleslaw I Chrobry ('the Mighty') born about 967 and died 1025; reigned 992-1025.
- Thyra Haraldsdottir
- Oda v.Haldesleben, princess of Ostmark .
Boleslaw I was married to:
- Heminilde von Meissen
- Judith von Bavaria, Hungary
- Oda von Meissen
In 997 he sent troops with St. Adalbert of Prague to Prussia at the Baltic Sea to attempt to convert the Prussians to Christianity. In 999 he conquered Silesia. He tried to conquer Danzig, Cracow, and Moravia.
In A.D. 1000 emperor Otto III visited the tomb of St. Adalbert at Gniezno; at that time he invested Boleslaw with the title Frater et Cooperator Imperii ("Brother and Partner of the Emperor"). Mieszko I and his son Boleslaw I had pledged allegiance to the emperors Otto I the Great, Otto II and Otto III and thereby received the office and title of duke in accord with the empire. On the same visit Otto III raised Gniezno to the rank of an archbishopric.
After the untimely death of Otto III in 1002 at the age of 22, Boleslaw I conquered the imperial March of Meissen and also Lausitz (Latin Lusatia), thereby trying to wrest imperial territory for himself during the disputes over the throne; he and his father had both backed Henry the Quarrelsome against Otto earlier, and he accepted the accession of Henry II of Saxony, the earlier Henry's son.
Boleslaw I Chrobry conquered and made himself duke of Bohemia 1003-1004, He defeated the Russians and stormed Kiev in 1018.
He was forced to give the pledge of allegiance by the next emperor Henry II again, for the lands he held in fief . When Henry died in 1024, Boleslaw I made himself king.
His son Mieszko II Lambert later also became king of Poland.