	After his death in 997 during a mission among the pagan Prussian tribes, Bishop Adalbert of Prague was quickly canonized by the common effort of Duke Bolesław I and Emperor Otto III. Thus, Adalbert became the first Slavic bishop to become a saint. His body, bought back by Bolesław from the Prussians for its weight in gold, was put into a tomb at Gniezno Cathedral, which became the ecclesiastical center of Poland.