In 1100, a nobleman named Heinrich named himself after the old Clingenburg (castle). He belonged to the noble family of Reginbodo. The Clingengurg castle was built around 1160-1170 by Conradus Colbo, who was cup-bearer to Emperor Friedrich Barbarossa.
About 1250, the Bickenbach noble family moved into the castle; the Bickenbachs later held many influential offices in the Holy Roman Empire and many a time turned up in Imperial politics as brokers.
After the Bickenbachs died out in 1500, the town, castle and lordly domain passed to the Archbishop of Mainz. Clingenburg castle was destroyed by the French in the late 17th century and never rebuilt. It remained a ruin.
In the 20th century Clingenburg was opened up to tourism with a restaurant and a lookout platform affording visitors a view over the old town and the Main valley. Since 1994, the Clingenburg-Festspiele have been taking place, drawing many visitors each year with changing plays and musicals.
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.