In the Middle Ages, Den Dool castle served as a summer residence for the abbots of the Abbey of Sint-Truiden. The first mention is from 1282. Around 1340 the first abbot, Amelius van Schoonvorst, was there as a refugee during the wars of Liège against prince-bishop Engelbert van der Mark. In 1361 the castle and farm were burned down by knight Hendrik van Halbeek. The castle was restored between 1443 to 1470. and again in 1522. It became a fortified mansion with a ring wall with towers and a deep canal.
Further enhancements were carried out by Abbot Hubertus van Sutendael (1638-1663), who had an entrance gate built in 1621 and a castle chapel in 1649. The complex was transformed in a classical style in the 18th century.
Den Dool was occupied by German soldies in the first and second World Wars causing damage to buildings. Since 1994, De Dool Castle Brewery has been located in the farm of the castle. Various restoration work was carried out in the following years.
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.