In the chronicle of Jan Długosz he is named the eldest son, but this is certainly a mistake, because elsewhere, Przemysław of Oświęcim was always placed before Bolesław.

Shortly after, Bolesław married Margareta, the sister of John II the Iron, Duke of Racibórz, who was the instigator of Przemysław's death.

The early death of Margareta shortly after the wedding contributed to the reconciliation between Bolesław and his father, which was formally signed on 7 September 1407.

Bolesław's second marriage in 1412 to Euphemia (called also Ofka), daughter of Duke Siemowit IV of Masovia, was probably suggested by King Władysław II Jagiełło of Poland (Euphemia's maternal uncle), who saw the opportunity to make close bonds between Upper Silesia and Kraków.

His alliance with Jagiełło quickly brought him results, as in 1414 Bolesław took an active part in the Polish-Teutonic War at the King's side.

In 1422, despite the Bohemian-Polish dispute, Bolesław was a guest at the court of King Władysław II Jagiełło, and took part in the coronation of his wife, Queen Sophia of Halshany.