Rabenstein Castle was built around 1100 to protect nearby Sankt Paul im Lavanttal. It began as a mere watchtower built on a tall hill. Rabenstein became a castle when Engelbert I Sponheim, Margrave of Istria founded St. Paul's Abbey in 1091 in order to protect the abbey and town around it. The castle was occupied by the Rabensteins (whose name henceforth stuck to the structure) until 1200, the Archbishop of Salzburg until 1300. in 1636 the castle was destroyed by fire and left to decay.
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.