After his brother Bolesław IV died on 3 April 1173, Mieszko III became the new high duke of Poland (
dux Totius Poloniae) according to the principle of
agnatic seniority. His policy focused on maintaining full power for himself, as the oldest surviving member of the dynasty. Despite his succession to the throne at Kraków, the new high duke remained in Greater Poland, while
Lesser Poland was ruled by
Henryk Kietlicz as a governor appointed by Mieszko. Harsh tax measures were introduced, which incurred the displeasure of the Lesser Polish
magnates. On the other hand, Mieszko had several foreign policy successes through his daughter's marriages:
Elisabeth married Duke
Soběslav II of Bohemia circa 1173, and through the dynastic arrangement between his daughter
Anastasia and the
Griffin duke
Bogislaw I of Pomerania, Mieszko reinforced Polish sovereignty over the
Pomeranian duchy. In 1177, Mieszko III's first-born son,
Odon, fearing for his inheritance, rebelled against his father. He was supported by Bishop Gedko of Kraków, his cousin Bolesław the Tall, and his uncle Casimir II the Just. For Odon, the main reason for his rebellion was the favoritism of Mieszko to the offspring of his second marriage and the attempts of the high duke to force him to become a priest so as to eliminate him from succession. To the other rebels, the reason was the harsh and dictatorial government of the high duke. The rebellion was a complete surprise to Mieszko; during Easter of 1177, he was totally convinced of the loyalty of his relatives, especially when the junior dukes organized a meeting at
Gniezno, where the high duke was received by the crowds with cheers. At first, Greater Poland remained strongly in Mieszko's hands, thanks to his governor,
Henryk Kietlicz, his most important follower. At the same time, Casimir II the Just, the clear head of the rebellion, made a divisionary treaty with his allies: all of Silesia was granted to Duke Bolesław the Tall and Greater Poland was given to Odon. This was a significant complication, because since 1173 Bolesław had ruled Silesia alongside his brother Mieszko Tanglefoot and his own son Jarosław of Opole. After they learned of this agreement, both Mieszko Tanglefoot and Jarosław sided with the high duke and rebelled against Bolesław the Tall, who now, busy fighting with his brother and son, lost the opportunity to gain Kraków and obtain the Seniorate Province for himself. In his place, it was Casimir II the Just who took control over the Seniorate Province, and, with this, was proclaimed the new high duke of Poland. After not seeing any possibility of continuing the resistance, Mieszko escaped to
Racibórz, under the protection of his nephew and namesake Duke Mieszko Tanglefoot. However, shortly afterwards, the deposed high duke decided to leave Poland and seek foreign support. Odon finally occupied all Greater Poland and was declared duke. == Exile and return to Greater Poland ==