Boleslaw I Chrobry ('Boleslaus the Brave') (966/967 - 1025) of the Piast family, son of Mieszko I and of his first wife, the Czech princess Dubrawka, ruled as duke of Poland from 992 to 1025 and reigned as King of Poland in 1025.
In 984 Boleslaus married Rikdaga, the daughter of Riddag (Rikdag, Ricdag), the margrave of Meissen. Subsequently he married Judith, the daughter of Geza the Great Prince of Hungary; then Enmilda, the daughter of one Dobromir, a Lusatian prince; and Oda, daughter of the margrave of Meissen. His wives bore him sons including Bezprym, Mieszko II and Otton; and a daughter, Mathilde. After death of his father around 992 he was able to expel the second wife of his father, Oda, with her sons, and unite the country again.
In 997 Boleslaus sent Saint Adalbert of Prague to Prussia on the Baltic Sea to attempt to convert the Prussians to Christianity. By this time he already possessed Silesia and Pomerania (with its main city of Gdansk) and Little Poland (with its main city of Cracow). In 999 he annexed present-day Moravia and in 1000 or 1001 Slovakia. He appeared well on track to uniting all West Slavic lands in one strong country as a member of Christian Europe.
In A.D. 1000, while on a pilgrimage to the tomb of St. Adalbert at Gniezno, the emperor Otto III invested Boleslaus with the title Frater et Cooperator Imperii ("Brother and Partner of the Empire"). Some historians say that the emperor also pledged the king's crown to Boleslaus. On the same visit Otto III accepted Gniezno's status as an archbishopric. For the consequences see the article on the meeting at the tomb of Saint Adalbert.
After the untimely death of Otto III in 1002 at the age of 22, Boleslaus conquered Meissen and Lusatia, in an attempt 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 Germany, the earlier Henry's son.
Boleslaus conquered and made himself duke of Bohemia and Moravia in 1003 - 1004; he defeated the Ruthenians and stormed Kyiv in 1018, annexing the Red Strongholds (Grody Czerwienskie) later called Red Ruthenia and making prince Sviatopolk his vassal there. The intermittent wars with Germany ended with the Peace of Bautzen, Budziszyn in 1018, which left Sorbian Meissen and Lusatia in Polish hands.
The emperor Henry II obliged Boleslaus to give a pledge of allegiance again for the lands he held in fief. After the death of Henry in 1024, Boleslaus crowned himself king, rising Poland to the rank of kingdom (1025).
The son of Boleslaus, Mieszko II crowned himself immediately after his father's death.
Boleslaus sent an army to aid his friend Canute in his conquest of England.
The Significance of Boleslaus's reign in the history of Poland
Boleslaus was the first Polish King, since during his rule Poland became a Kingdom, despite the fact that some of the Polish rulers before 1295 never received a crown. He was the first Polish ruler baptised at birth, the first real Christian ruler. He founded the independent Polish province of the church and made Poland a strong power in Europe. Boleslaus for the first time unified all the provinces that subsequently came to comprise the traditional territory of Poland: Greater Poland, Little Poland, Masovia, Silesia and Pomerania. For the Sorbs of Lusatia he became the national hero.