Tellenburg Castle was built around 1200 by the Lords of Kien. After the Lords of Kien, the Lords of Wädenswil became the owners of the castle. They were followed by the Lords of Turn in 1312 and then later by the city of Bern. The original castle was expanded and repaired in the 13th or 14th centuries.
Under Bernese rule, the castle served as the administrative seat of the surrounding area until the creation of the Helvetic Republic in 1798. After 1798 it was used as a poor house. In 1885, the castle was gutted in a fire. It was never rebuilt and has slowly fallen into ruin.
Tellenburg Castle was built as an administrative center and toll station. Telle at beginning of the name likely comes from the German word for toll, Zoll, while burg simply means fortress.
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.