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 of Poland Quedlinburg in 973 to explain and justify their conduct. The exact judgment of the Emperor is unknown, but it's certain that the sentence wasn't carried out because he died a few weeks after the Diet. It is commonly assumed that the sentence was unfavorable to the Polish ruler. The "Annals of Altaich" indicates that Mieszko was not present in Quedlinburg during the gathering; instead, he had to send his son Bolesław as a hostage. Mieszko's conflict with Odo I was a surprising event because, according to Thietmar, Mieszko respected the Margrave highly. Thietmar wrote the following: It is believed that