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 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,