At the Southwest tip of the Inchmurrin island are the ruins of the 14th century castle built by Duncan the Eighth Earl of Lennox. The castle is recorded as having been completed by 1393 and the Earls of Lennox took up residence in the 14th century when they moved from their castle in Balloch during the plague. The castle was composed of three rooms, outbuildings and a courtyard.
King Robert the I is believed to have been given refuge here by the Fifth Earl of Lennox after his defeat by the MacDougalls of Lorne. King Robert the I also established a deer park here in the 14th century.
Isabella, countess of Albany and the daughter of the Eighth earl of Lennox was exiled here after 1425 when her husband, father and two sons were all executed on the same day at Stirling by King James I. She lived at the castle for the rest of her life and died on the island in 1460 after which the castle was abandoned. It is recorded that Sir John Colquhoun of Luss was killed here in 1439 during a raid led by Lachlan MacLean.
King James the IV used the castle as a hunting lodge around 1506 as did King James the VI in later years.
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.