This Norwegian fortress was constructed in the 17th century as a replacement for the border fortress at Bohus, which had been lost when the province of Bahusia was ceded to Sweden by the terms of the Treaty of Roskilde in 1658. The fortress was named after King Fredrik III of Denmark and Norway, and the town of Halden was also originally named after him, having been known as Fredrikshald between 1665 and 1928.After 1905 the fortress lost all military significance, but it still hosted various units. As of today the Norwegian defense logistics and administrative college is situated by the fortress. The fortress also hosts several museums, and art exhibitions. Visiting the fortress is rather popular as its very scenic with old buildings and the location on the cliff above the small city adds to its beauty.