 During the Fragmentation of Poland, Silesia and the rest of the country were divided among many independent duchies ruled by various Silesian dukes.During this time, German cultural and ethnic influence increased as a result of immigration from German-speaking parts of the Holy Roman Empire.In 1178, parts of the Duchy of Kraków around Bytom, Oświęcim, Chrzanów, and Siewierz were transferred to the Silesian Piasts, although their population was primarily Vistulan and not of Silesian descent.