His first decision as an independent ruler was caught up in conflict with the Bishop of Kraków, Zbigniew Oleśnicki, who purchased Siewierz from the Dukes of Cieszyn.

The agreement signed between both parties on 18 February 1447 in Kraków, was short-lived: on 6 October 1450 Przemysław attack with his troops the Bishop's castle in Siewierz.

Soon the brother's troops were defeated and they were prompted to issue a document (7 March 1453), in which Przemysław took all the responsibility for the war, declared the freedom for all the prisoners, and paid 2,000 fines as a compensation.

It wasn't until 25 July 1479 when the Duke of Toszek received a guarantee of his government, but in exchange he was compelled to paid homage to Bohemia.

They had one daughter: After his death without male issue, the Duchy of Toszek was inherited by his brother Jan IV, but almost immediately the land was confiscated by King Matthias, who claimed more dubious rights to them.