The Romanesque part of the Church of Saints Peter and Paul is from around 1120. Next to the church stands as a remnant of the church fortifications an old bastion from 1278, which is transformed into a bell tower. The bell in the bell tower is from 1512. There is also one of the rarest Czech sights, the Načeradský Missal from the 13th century.
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.