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,
Bolesław I the Brave Mieszko II) that gave the King his widely known nickname of "Brave" (Polish: "Chrobry") -later Gallus Anonymus in the Chapter 6 of his "Gesta principum Polonorum" named the Polish ruler as "Bolezlavus qui dicebatur Gloriosus seu Chrabri". The contemporaneous Thietmar of Merseburg recorded Bolesław's marriages, also mentioning his children. Bolesław's first wife was an unnamed daughter of Rikdag, Margrave of Meissen. Historian Manteuffel says that the marriage was arranged in the early 980s by Mieszko I who wanted to strengthen his links with the Saxon lords and to enable his son to succeed Rikdag in Meissen. Bolesław "later sent her