Saints Peter and Paul Mother Church stands on the site of an early church which dated from 1212, retaining its bell tower and two of its stained glass windows. In 1542 it was expanded by the addition of two extra aisles, constructed by Pietro and Antonio Laviola, two brothers who were later accused of murder in Mantua.
The church is in the Romanesque-Renaissance style, with an angled roof, and is built in the shape of a Latin cross, with three aisles. On the left and right there are small chapels, under which there are buried local important people. Each chapel has a statue by the sculptor Salvatore Sacquegna. The interior walls of the church are decorated with 18th-century pictures painted by Domenico Guarino, among which Our Lady of Mount Carmel, the Madonna del Pozzo, and the Mysteries of the Rosary are especially notable.
Visby Cathedral (also known as St. Mary’s Church) is the only survived medieval church in Visby. It was originally built for German merchants and inaugurated in 1225. Around the year 1350 the church was enlarged and converted into a basilica. The two-storey magazine was also added then above the nave as a warehouse for merchants.
Following the Reformation, the church was transformed into a parish church for the town of Visby. All other churches were abandoned. Shortly after the Reformation, in 1572, Gotland was made into its own Diocese, and the church designated its cathedral.
There is not much left of the original interior. The font is made of local red marble in the 13th century. The pulpit was made in Lübeck in 1684. There are 400 graves under the church floor.