Visby Cathedral (Swedish: Visby domkyrka), formally Visby Saint Mary's Cathedral (Visby S:ta Maria domkyrka) is a cathedral within the Church of Sweden, seat of the Bishop of Visby. It lies in the centre of Visby, the main town on the Swedish island Gotland. It was built as the church of the German traders in the city during the 13th century. The very first church was probably a wooden church, which was later replaced by a stone building. Originally built as a basilica, it was successively expanded and rebuilt during the Middle Ages. At the end of this period it had been transformed to a hall church, which it still is. In 1361, Gotland and the church became part of Denmark. Following the Reformation, it was the only medieval church in the city left in use, and in 1572 raised to the status