In the early 13th century the Teutonic Order launched its first crusades to the territories around the central stretch of the River Nogat in order to convert the local inhabitants to Christianity. At the beginning of the 1380s the Teutonic Knights started building a castle here which they referred to as St. Mary's Stronghold (German Marienburg). In less than 30 years they raised a quadrangular convent building complete with chapel, chapter house, dormitory, refectory, an enclosed courtyard and a bailey situated to the north. A long, high gallery was built leading from the south-west corner to the Danske or sewage-tower, which was also used for defence purposes…