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 I of Poland socially connected primarily by tribal structures. It appears that the elders cooperating with the Duke first felt the need for super-tribal unity, as expansion allowed them to broaden their influence. Mieszko and his people were described around 966 by Abraham ben Jacob, a Sephardi Jewish traveller, who at that time visited the Prague court of Duke Boleslav I the Cruel. Abraham presented Mieszko I as one of the four Slavic "kings", reigning over a vast "northern" area, with a highly regarded and substantial military force at his disposal. More precise contemporary records regarding Mieszko were compiled by Widukind of Corvey,