Mieszko II Lambert by the chronicles of Gottfried of Viterbo, refers to Bezprym. However, the historians now think that he was killed in a plot hatched by the aristocracy. He was buried in the Cathedral of St. Peter and St. Paul. After Mieszko II's death, Poland's peasants revolted in a "pagan reaction." The exact reasons and date are unknown. Mieszko II's only son and heir, Casimir I, was either expelled by this insurrection, or the insurrection was caused by the aristocracy's expulsion of him. Some modern historians argue that the insurrection was caused more by economic than by religious issues, such as new
Mieszko I, Duke of Cieszyn shelter to the Bishop in Raciborz. His politics against Henry IV were reinforced when the Duke of Wrocław repudiated his wife Constance —sister of Mieszko— and sent her back to her homeland. Another consequence of Mieszko's politics was an armed expedition of Henry IV in 1287 against Racibórz, who was sieged. Then Mieszko was forced to refuse his help to the Bishop. In 1290 the division was made of the Duchy of Racibórz: Przemysław retained Racibórz and Mieszko obtained the rule over the districts of Cieszyn, Oświęcim and Zator. The first time that he signed himself as Duke of Cieszyn