The oldest part of the Ösmo Church was constructed in the latter part of the 12th century. The church was modernized in the 14th century, when the old chancel was demolished and replaced by one which was both taller and wider. The church largely gained its present appearance during the 15th century.
The interior of the church is decorated with frescoes added just after the middle of the 15th century. It is said that they were painted by Albertus Pictor, the most famous church artists of the medieval period. The church also contains a large number of coats of arms used in processions, and a triumphal crucifix.
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.