The Livonian Order erected Grobiņa Castle in 1253 to protect the roads from Livonia to Prussia. It was a square type building and was a three storey high living block in the southern aisle. It also had a gate tower in the middle of the western wall. The castle was built of bricks and crude stone. Once it had arched ceilings. It was a residence for the local viceroy of the Livonian Order from 1399 to 1590. As support base in south Courland it was many times rebuilt and fortified.
In the times of the Duchy of Courland, the castle was destroyed and rebuilt many times. In the sixteenth and seventeenth century sand walls were erected around the castle. They had a bastion in each of the four corners and a stockade. Later the castle was used as a residence for local German landlords. The castle was destroyed in the eighteenth century. Many famous people have visited the castle, for example: Duke Jacob Kettler of Courland, The King of Sweden, Carl XII and the King of Prussia, Friedrich Wilhelm III.
In the 1970s major conservation jobs were made in the castle, so today the castle ruins are in a quite good condition. Most of the walls are still standing in three story height. Today's castle is a major tourist attraction and also a place for local gatherings and concerts.
The ancient Curonian castle hill (Skābāržu kalns) is located only 100 m from the castle. It is supposed to be the famous Seeburg, which is mentioned in Scandinavian sources already in 9th century.
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.