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 was on 1 January 1290. In internal politics he pursued vigorous policies. Mieszko carried out intensive colonizing policies and founded many settlements. He also gave city rights to several towns: Cieszyn, Oświęcim (in 1291), Bielsko, Skoczów and Fryštát. On 10 November 1292 he granted the city rights to Zator. Mieszko refused to support any of the Piast pretenders to the Polish throne (Henry IV Probus, Przemysł II and Władysław I the Elbow-high). Instead he stood alongside King Wenceslaus II of Bohemia. On 17 January 1291 the formal agreement was signed in Olomouc which formed the alliance between the Bohemian Kingdom,