His independent rule began on 23 June 1404, when, under the provisions of King Wenceslaus IV of Bohemia, the young prince received as a fief Góra Śląska and half of both Głogów and Ścinawa (although some historians stated that this diploma refers to his father, Duke Przemysław I Noszak).

The circumstances of the young Duke's murder were known thanks to the Chronicle of Jan Długosz, who describes these events but with the incorrectly date of 1 January 1400.

By that time, Przemysław was still alive, as is proved in a document from 1402 concerning to the acquisition of Oświęcim, which could take place in early 1405.

The Duke of Oświęcim, while traveling from Gliwice to Cieszyn, was killed in the town of Rybnik by a certain Martin Chrzan.

The punishment given to the murderer Martin Chrzan was colorfully described by Jan Długosz: He (the murderer) was placed on the bronze horse who was in the middle of incandescent coals and this showed in all the Cieszyn streets; later the three executioners cut his body into pieces, and they finally were thrown into a river.