Colombier Castle was built in the 11th or 12th century as a fortified tower over the ruins of the Roman villa. It expanded in the 13th Century and by the 16th century had reached its present appearance.
One of the largest Roman era villas in Switzerland was excavated from under the castle in 1840-42 by Frédéric Dubois de Montperreux. It was built in multiple stages between the 1st and 3rd centuries AD into a palatial mansion with a peristyle, at least two baths with mosaics and frescoes and terraced gardens.
In 1806, Colombier Castle was converted into a military hospital. Starting in 1824 it was used by the Federal militias as a parade ground and was converted into a barracks and given an expanded arsenal. In 1877 it became the official barracks of the 2. Division, which later became Field Division 2. In 2003, the Army XXI reforms dissolved the Division and in 2004 the barracks became an infantry training center.
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.