Norway- Fredriksten Fortress in Halden

This Fortresses was constructed by Denmark-Norway in the 17th century as a replacement for the border fortress at Bohus, which had been lost when the province of Bohuslän 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.