In the 13th century, the San Juan del Hospital Church was the priory of the Knights of the Order of St. John of Jerusalem with a hospital attached and it was converted into a military parish in the 18th century. Built around 1261, it is considered to be the first church built after the Christian conquest. Its combination of the synthesis and elegance of Romanesque tradition with the new gothic architecture and the fact that it has the only cemetery dating from medieval times in Valencia, led to its classification as a National Historic and Artistic Monument in 1942.
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.