Mieszko I of Poland death occurred from causes other than natural. According to Thietmar the Polish ruler died "in an old age, overcame with fever". Probably he was buried in the Poznań Cathedral. The remains of the first historical ruler of Poland have never been found and the place of his burial is not known with certainty. In 1836–1837 a cenotaph was built for Mieszko I and his successor Bolesław I the Brave in the Golden Chapel () at the Poznań Cathedral, where the damaged remains found in the 14th century tomb of Bolesław were placed. According to Thietmar Mieszko I divided his state
Mieszko II the Fat and was succeeded by his son Henry II the Pious, who also assumed the regency over Opole-Racibórz. Shortly after, Mieszko II began to claim the government of their lands. It is unknown exactly when Mieszko II took over the rule over Opole-Racibórz, but this has been probably in late 1238 or early 1239 (who is more likely). One of the first politic decisions of Mieszko II was his marriage with Judith (b. 1222/25 – d. 4 December 1257/65?), daughter of Duke Konrad I of Masovia, who gave to the Duke of Opole-Racibórz greater autonomy in his rule. Mieszko II's mother