St. Nicholas Cathedral is a Gothic church established in circa 1247. When the burghers of Elbing (Elbląg) first attempted to adopt the Protestant Reformation in 1525, the provost of St. Nicholas Church maintained Catholic practice. Since 1539 the city council tacitly tolerated and gradually openly promoted Lutheranism, so that St. Nicholas Church had become a Lutheran church by 1573.
Following King Sigismund III's Prussian regency contract (1605) with Joachim Frederick of Brandenburg and his Prussian enfeoffment contract (Treaty of Warsaw, 1611) with John Sigismund of Brandenburg these two rulers of Ducal Prussia guaranteed free practice of Catholic religion in prevailingly Lutheran Prussia. Based on these contracts Prince-Bishop Szymon Rudnicki of Ermland/Warmia achieved the restitution of St. Nicholas as Roman Catholic parish church in 1612, then the only one in Elbing, and remaining a Catholic church since.
St. Nicholas was damaged by fire in the late 18th century, then destroyed in World War II and reconstructed. In 1992, the building was elevated to the status of cathedral.
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.