They took advantage of the tensions within the Piast dynasty and the fragmentation of the former Duchy of Silesia north of the Bohemian borders.

By promises as well as by pressure, with the exception of Duke Bolko II the Small, an increasing number of the Silesian Piasts had recognized the sovereignty of Charles' father and predecessor, King John of Bohemia, from 1327 to 1335.

When King Casimir III succeeded his father Władysław I the Elbow-high in 1333, he found the Polish borders threatened not only by the Bohemian kingdom, but also by the Margraves of Brandenburg, who had extended their territory further eastwards into the Neumark region, and foremost by the State of the Teutonic Order, whose plans for expansion had sparked the Polish–Teutonic War (1326–1332) over Pomerelia, Kuyavia and the Dobrzyń Land.

After tensions had settled, Casimir acted cleverly in the rising conflict between the Luxembourgs and the Imperial House of Wittelsbach around the heritage of Countess Margaret of Tyrol.

He was able to convert Emperor Louis IV to his column and occupied several Silesian territories south of the Polish border, including the castle of Namysłów.