The Ahrensburg village came into the possession of the Cistercian Reinfeld Abbey in 1327. After the dissolution of the monasteries due to the Reformation, the whole area came into the possession of the king of Denmark. He rewarded his general Daniel Rantzau 1567 with lordship over these villages. His brother and heir Peter Rantzau built a Renaissance residence in the form of a water castle, now the symbol of the town, and the castle church around 1595. The new schloss buildings were made with parts of the torn-down mansion, on a rectangular island surrounded by a defensive moat. The following year, the chapel was completed. It was modelled on Schloss Glücksburg, built a few years earlier. Four octagonal towers were added later with copper-covered torn heads and lanterns.
The Rantzaus' estate was heavily indebted by the middle of the 18th century and, in 1759, was acquired by the businessman Heinrich Carl von Schimmelmann. Schimmelmann remodelled the castle and village in the baroque style and the current layout of the town reflects these plans.
Historians in Germany consider the building one of Schleswig-Holstein's best-known Renaissance buildings and attractions. Open to the public, it is surrounded by an English park, a chapel, a watermill and a museum.
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.