The Château de Roquessels was built in the 10th century. It was a dependency of the convent of Cassans, which collected tithes from the baron of Margon. In 1247, the inhabitants of the village, like all subjects of the Trencavels, viscount of Béziers, were released from their pledge of allegiance and submitted to the King of France. The castle resisted valiantly the assaults of Simon de Montfort's army. Today, the only remains are a chapel with fine windows and massive walls on three sides.
The castle was abandoned for more comfortable dwellings in the 18th century, in line with the changing tastes of the aristocracy of the period. The keep was destroyed during the French Revolution and its stones used to build the new mairie (town hall).
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.