The ancient village of Roccavaldina was conquered by Romans, Byzantine and Arabs. Later in the Middle Ages, it was ruled by Roger I, who built numerous monasteries with the aim to spread the Christian culture over the area. The Valdina Castle was built as a stronghold in the 16th century and later transformed in a prive aristocratic house; the Chemistry Museum is an ancient shop created in 1628 which contains over 200 apothecary jars made with the local ceramics.
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.