Hagby Church is one of Sweden's few preserved round churches, and is considered by many to be the best preserved one in the country. The predecessor of Hagby stone church was the wooded Saint Sigfrid chapel, which was located about two kilometres south of the present church structure. The construction of this stone church began in the late 12th century. By 1541 it was abandoned.
The structure was meant to serve both as a sanctuary and a fortified building. As a result, the upper part of the walls has openings for shooting and spear throwing. The most recent renovation has attempted to emphasize the old nature of the building, so that it is now perhaps the best example of round church architecture, which otherwise is generally mostly found on the island of Bornholm. The triumph crucifix and font dates from the Middle Ages, but the interior is mainly from the 17th and 18th centuries.
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.