St. Michael's Church was built in the Early-Gothic architectural style, first mentioned in 1282, in 1449 burned down by a fire and subsequently rebuilt. The expansion work on the church in the fifteenth and sixteenth-century was blighted by the Thirty Years' War and as such was burned down again. Prior to 1671, the church was renovated by Bishop of Wrocław, Sebastian von Rostock. The church was restored in 1893.
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.