Mieszko I of Poland elders, and limited their authority. Clergy who arrived in the country contributed to the development of education and culture, and of the state administration and diplomacy, as well. At the end of Mieszko's reign (ca. 990), Poland began to pay tribute to the pope (Peter's Pence). However, the conversion of the Polish population to Catholicism was a long-term process, and was not completed during the reign of Mieszko I. The duke probably had to deal with rebellions led by the old pagan priest caste. In some villages, the old Slavic beliefs and customs were continued until the 16th century. After
Mieszko III the Old several foreign policy successes through his daughter's marriages: Elisabeth about 1173 married Duke Soběslav II of Bohemia and through the dynastic arrangement between his daughter Anastasia and the Griffin duke Bogislaw I of Pomerania, Mieszko once again reinforced Polish sovereignty over the Pomeranian duchy. In 1177 Mieszko'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 the Just. For Odon, the main reason of his rebellion was the favoritism of Mieszko to the offspring of his second marriage and the attempts