The Church of St. Nicholas is an Eastern Orthodox Church in the Bulgarian capital of Sofia. The church was built in the 13th century by Kaloyan the sebastocrator as a small family church on today's Kaloyan Street behind the Rila Hotel. It is assumed that the church was erected on the site of the surviving parts of the palace complex that had once stood there which was built during the Roman Empire and accommodated Constantine the Great. Today these parts are preserved and can be seen in the authentic underground walls of the temple.
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.