Fredrikstad fortress was constructed between 1663-1666 by the officer Willem Coucheron and his son Anthony Coucheron following the order of the Dano-Norwegian King Frederick II. A temporary fortification had previously been built on the site during the Torstenson War (1644-1645) between Sweden and Denmark-Norway.
The first commander was appointed 6 January 1662; he was Lieutenant Colonel Johan Eberhard Speckhan. Besides the fortress the prison works was also under the supervision of the commander of Fredrikstad fortress. In 1716 the fortress was used by the naval hero Peder Tordenskjold when he attacked the Swedish fleet during the Battle of Dynekilen.
The only time the fortress were attacked was during the Swedish-Norwegian War (1814). The fortress, under the command of Nils Christian Frederik Hals, capitulated on 4 August 1814. The fortress was closed in 1903, but continued to serve as a garrison. Fredrikstad fortress is unique in Norway by being the only fortress that is preserved as it was. The remaining military installations in Fredrikstad were closed in 2002 and today the fortress with its mix of old buildings and art exhibitions is very popular for visitors.
The fortifications in Fredrikstad include Kongsten fort, Isegran fort, Cicignon fort, Huth fort, Akerøya fort and Slevik battery.
References:The Walls of Constantinople are a series of defensive stone walls that have surrounded and protected the city of Constantinople (today Istanbul) since its founding as the new capital of the Roman Empire by Constantine the Great. With numerous additions and modifications during their history, they were the last great fortification system of antiquity, and one of the most complex and elaborate systems ever built. They were also the largest and strongest fortification in both the ancient and medieval world.
Initially built by Constantine the Great, the walls surrounded the new city on all sides, protecting it against attack from both sea and land. As the city grew, the famous double line of the Theodosian Walls was built in the 5th century. Although the other sections of the walls were less elaborate, they were, when well-manned, almost impregnable for any medieval besieger.