St. Peter's Cathedral in Bremen has a long and significant history. As the seat of the missionary bishopric in the early Middle Ages, the Christianization of Scandinavia and the Baltic peoples started from Bremen. After a fire, the church was rebuilt as a Romanesque structure in the 11th century, which still determines the cathedral's dimensions and structure today. In the Gothic style, the northern nave was remodeled in the later Middle Ages, and the towers also received Gothic helmets. In addition to several special organs, including a Sauer and a Silbermann organ, a small church mouse can be found in the interior, which was depicted by a stonemason in the 13th century on the high choir.