The story and the experience starts in 1644. Norway was for hundreds of years in union with Denmark, and Denmark-Norway and Sweden repeatedly were at war. One war took place in the years 1643-45. At this time basic fortifications were built from timber on the mount overlooking Halden.
However, there was no attack from the Swedes those years.
Up to 1658 the county of Bohuslän located between Halden and Gothenburg belonged to Norway. The mighty border fortification, Bohus, 20 km north of Gothenburg were built in the early 1300 and later expanded and modernized.
After yet another defeat against the Swedes in the winter of 1657-58, the Danish king Frederick III had to defer the county of Bohuslän and several Danish owned areas to the Swedes. With the stroke of a pen the Swedish border moved to the Idde-fjord and the small seaport, Halden.