Landskron castle itself was probably built in the early 13th century. Is first mentioned in 1244. This castle was destroyed in 1257 and 1275 by the rebellion Oppenheim citizens. It was rebuilt in 1281.
The castle burned down in 1621 during the Thirty Years War. In the Nine Years War, French troops blew up the keep in 1689 to keep. In the following years the citizens used the ruins as a quarry.
References: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.