Nyborg is a city in central Denmark, located in Nyborg municipality on the island of Funen. The population is 15,862 (2004). Nyborg was first mentioned in 1193 in the history of Denmark as Nyborg Castle, which still exists today, but the town itself was not mentioned before the year 1202. In the 17th century, Nyborg was one of three major, fortified towns in Denmark. The two others are Fredericia and Copenhagen. Each was placed near an important body of water - in Nyborg's case, the Great Belt (Storebælt). In 1659 the city was captured by the Swedes and relieved by an expeditionary fleet sent by the Dutch, then Denmark's allies, commanded by admiral De Ruyter. In 1867 the fortress was abolished and the town expanded beyond the ramparts. Much of the town's southern ramparts were destroyed in this process and converted into residential areas. The western and much of the northern ramparts still exist and form the scene of an annual theatre known as Nyborg Voldspil.