Lands of the Bohemian Crown
Silesia was incorporated into the Lands of the Bohemian Crown, after King Casimir III had acknowledged the acquisition by the 1348 Treaty of Namslau with King Charles IV — except for the Upper Silesian duchies of Oświęcim and Zator, which in the 16th century were integrated in the Polish Kraków Voivodeship, as well as the Duchy of Siewierz, that was purchased by the Archbishop of Kraków in 1443.