Shortly after the year 1000, the bishops of Poitiers from the Isembert family, succeeding a family named Chauvigny, became lords of Chauvigny, and later barons from the 14th century onward. The baronial castle, also known as the Bishops’ Castle, was built in the 11th century by them. The quadrangular keep dates from the mid-11th century. Starting in 1397, Ithier de Mareuil, bishop of Poitiers from 1394 to 1405, added a second keep to the castle. Today, it hosts falconry shows.
The structure is a complex building, 80 meters long and 50 meters wide. It was frequently damaged and altered. By the late 17th century, it was already nearly abandoned.
You can still see a first enclosure with the original 11th-century entrance, a powerful 12th-century keep, the ruins of the 'new castle' built around 1400 (of which an impressive wall section remains, showing two stories of apartments) and the Saint-Michel chapel with its chapter room above. Access to the inner courtyards and buildings of the second enclosure (12th–16th centuries), including kitchens, bakeries, stables, a well, and a tunnel, was via a drawbridge. The castle chapel can be recognized by its vaulted ceiling bearing the coat of arms of Ithier de Mareuil.
The castle's current ruined state is due to its sale as national property during the French Revolution, after which the buyer turned the fortress into a stone quarry.
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.