The Kassari Manor, also called Saaremõisa (’Island Manor’), was founded in this location by David Johan Gaertner, the archivist of the Est- land Supreme Land Court, in 1730s. In 1758, the Stackelbergs became its new owners. That Baltic German family took care of and managed the Kassari Manor until the beginning of the 20th century.
One of the buildings that once belonged to the old manor and that have survived is the stone-built steward’s house, which later housed a school, a library and a post office and is now one of the sites of the Hiiumaa Museum. Other buildings surviving from the manor are the stone-built stable, the gardener’s house, granary and the big Dutch-style windmill. Here and there, one can also spot the remnants of the limestone wall, once surrounding the manor centre, as well as the foundations of some buildings.
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.