Among Greifswald's brick gothic churches is the Dom St. Nikolai (St. Nicholas collegiate church) in the town center, which, with its tall tower, is the symbol of the city. The exact date of its founding is unknown, but the original church dates from the late 13th century. The tower was built, and an organ installed in the church, in the late 14th century. In the mid-17th century, when Greifswald was part of Swedish Pomerania, severe storm damage was repaired with support from the Swedish Crown. Neglect during the early DDR period necessitated extensive refurbishment, completed in 1989, the last full year of the DDR.