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
Bolesław I the Brave Mieszko II) that gave the King his widely known nickname of "Brave" (Polish: "Chrobry") -later Gallus Anonymus in the Chapter 6 of his "Gesta principum Polonorum" named the Polish ruler as "Bolezlavus qui dicebatur Gloriosus seu Chrabri". The contemporaneous Thietmar of Merseburg recorded Bolesław's marriages, also mentioning his children. Bolesław's first wife was an unnamed daughter of Rikdag, Margrave of Meissen. Historian Manteuffel says that the marriage was arranged in the early 980s by Mieszko I who wanted to strengthen his links with the Saxon lords and to enable his son to succeed Rikdag in Meissen. Bolesław "later sent her