Sterkenburg Castle was probably built in the mid-1200s as a moated round tower house by a Gijsbert van Wulven. The castle remained in the hands of the Van Wulven family until 1456 when it came into the possession of a Wouter van Ijzendoorn through marriage. It remained in their possession for the following hundred years. During their ownership the castle was rebuilt; a square tower was added and a curtain wall was built along the edges of the castle island creating a courtyard between the 2 towers and giving the castle a polygonal shape. Also the round tower was raised with extra floors.
In 1565 Sterkenburg Castle was owned by Reinier van Aeswijn, who was married to the last female Van Ijzendoorn descendant. He allowed a garrison of State troops to be quartered at the castle to protect it and the surrounding lands from the Spanish at the beginning of the 80-Years War. His son Antonie added a gatehouse to the bailey in 1626. In 1646 he left it to his nephew. This nephew however got murdered in the castle's woods in June 1647. This murder was never solved. The following decades Sterkenburg Castle changed ownership several times due to inheritance issues after a couple of untimely deaths.
In 1725 however the castle was bought by a member of the Mamuchet family. This family didn't live in the castle and it was rented out.
In 1741 the, by then decayed, castle was obtained by a member of the Van Westrenen family. The second Van Westrenen partially rebuild the castle's south side, opening up the courtyard demolishing the square tower and replacing it with a new wing on the old foundations.
In 1829 the castle was sold at a public auction to a PA. Hinlopen and his wife. They again sold the castle in 1848 to Karel Kneppelhout. He pulled down the entire castle, with exception of the round tower, and build a new house on the foundations. The round tower was provided with large windows and in 1867 he also added a square tower to the new wing. The present form of the castle is mainly the outcome of his rebuilding.
In 1978 the castle was again sold and used for private habitation. At present the castle can be rented for cultural activities and as an B&B. The castle has its own website at: Kasteel Sterkenburg.
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.