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 Czech language and had to come from Dobrawa's entourage and the church elements that arrived with her. Perhaps with her also came the first Polish bishop, Jordan. It could be that the reason for the Czech preference of Mieszko was the existence in Bohemia of a mission which followed the precepts of the Byzantine Greek brothers and later saints Cyril and Methodius, who developed and performed the liturgy in the Slavic rite, more readily understood by Mieszko and his subjects. The Slavic rite church branch had survived in Bohemia for another hundred years after Mieszko's baptism. Through the adoption of