History is palpable on the peaceful and quiet Cathedral Island (Ostrów Tumski). Excavations revealed the presence of a church on this site for more than a millennium. It is believed that Mieszko I (father of Poland's first crowned king, Bolesaw the Brave) was baptized here in the 10th century. The crypt holds the rubble of the baptism bowl. Architectural tinkering and rebuilding through the years, and the 1945 fire in the cathedral, have greatly altered its appearance, giving it the current ensemble of everything from pre-Romanesque to Gothic, baroque, and classicist. Eclecticism is also seen in the naves and chapels. The most eye-catching features are the frescos, dating from 1616, depicting the 12 apostles; the 19th-century Golden Chapel, with unabashedly brazen Byzantine designs; the crypt containing the remains of Mieszko and Bolesaw the Brave; and the four Vischers bronze plaques that were looted by the Nazis, recovered by the Russians, and returned to the cathedral in 1990.
The cathedral has no guide service. If you want a guide, make arrangements at the city's tourist center. To cover the crypt and the major artifacts, it's about 1 1/2 hours.