The cathedral is known for its twelfth-century (ca. 1175), two-winged bronze doors decorated with scenes of martyrdom of St. Adalbert of Prague and a silver relic coffin of that saint. The coffin was made by Peter von der Rennen of pure silver in 1662 after the previous one, established in 1623 by King Sigismund III Vasa himself, was robbed by the Swedes in 1655, during the Swedish invasion.