Mieszko the Younger time in 1166 or 1167 in a document signed between Mieszko III and Casimir II the Just at the congress in Jędrzejów as one of the sons of the Duke of Greater Poland. Between 1177 and 1179, as a result of the revolt against his father, Mieszko, with his parents and siblings, were exiled from Poland. They probably returned to the country in 1181, when Mieszko III regained the rule over Greater Poland. In 1184 and thanks to the wise diplomatic affairs of his father, Mieszko the Younger was appointed by the sickly Duke Leszek Governor of the Masovian-Kuyavian principality,
Mieszko I, Duke of Cieszyn the church. Thanks to him, the construction was completed of the Dominican convent at Oświęcim (shortly after 1283). Also, he financially assisted the monastery of Czarnowąsy near Opole and in the Dominican of Cieszyn. Mieszko's exact date of death is unknown. Diplomatic sources suggest that he died in 1314 or in the first half of 1315, before 27 June. He was probably buried in the Dominican church in Cieszyn. In 1931 the Polish painter and sculptor Jan Raszka made a sculpture of Mieszko I in Cieszyn. According to some sources, Mieszko's wife died around 1303, but her name is unknown.