Ruins of Aose Castle are located close to the port of Åhus. This fortress, probably built in the 12th century and again in 1286, was protected by a high wall and a moat spanned by a drawbridge. It was destroyed in 1569 by Duke Karl, later to become King Karl IX of Sweden, and the ruins were gradually covered by drifting sand before being excavated in the late 1800s. It has always been widely assumed that the castle was built on the orders of Archbishop Eskil, but recent excavations have revealed new evidence that suggests that Canute the Great, King of Denmark and England, was the first lord of Aose Castle.
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.