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 II Lambert name for his son was an expression of warming relations between Bolesław I and his stepmother Oda. He organized two devastating invasions to Saxony in 1028 and 1030. Then Mieszko II ran a defensive war against Germany, Bohemia and the Kievan princes. Mieszko II was forced to escape from the country in 1031 after an attack of Yaroslav I the Wise, who installed Mieszko's older half-brother Bezprym onto the Polish throne. Mieszko took refuge in Bohemia, where he was imprisoned by the Duke Oldrich. In 1032 he regained power in one of the three districts, then united the country, making