Bolesław I Chrobry
The baptismal mission which began in the two major cities of Gniezno and Poznań with the baptism of Mieszko and his court spread throughout the country. During the 10th and 11th centuries various ecclesiastical organs were established in Poland. This included the building of churches and the appointment of clergy. The first Bishop of Poland, Jordan, was appointed by Pope John XIII in 968. Mieszko's son Bolesław I Chrobry supported Christianization missions to neighboring lands, notably the mission of future Saint Adalbert of Prague to Old Prussians, and established the Archbishopric of Gniezno in the year 1000.