Fredriksten Fortress 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. Fredriksten took part to the battle first time two years later, in January of 1660, when the Swedish forces attacked Halden for the third time. After the attempt to storm the fortifications was unsuccessful, the Swedes prepared a regular siege. On 22 February 1660 the Swedes again were forced to retreat to Bohuslen until they heard that their king Charles X had died.
The existing star shaped fortress complex was upgraded during the period of peace between 1661–1675. In 1673 Denmark dispatched Ulrik Frederik Gyldenløve as statholder to Norway to organize the military forces and strengthen the defenses of the kingdom. After a tour of facilities, he recommended further upgrades to both the fortress and the military forces. In the summer of 1675, 1800 men were kept at work on the fortresses at Akershus, Fredrikstad, and Fredrikshald. Fredriksten was expanded from 1682–1701. It now included three outer fortifications: Gyldenløve, Overberget and Stortårnet.
At the close of the Great Northern War Charles XII of Sweden attempted to take Frederiksten by storm on 4 July 1716. His troops took the town after fierce fighting, but the citizens set fire to their own houses, forcing Charles, unable to take the fortress, to retreat and await the arrival of heavy siege guns. Unfortunately for the invading army the entire Swedish transport fleet was captured or destroyed by the Norwegian naval hero Tordenskjold at the Battle of Dynekilen in Bohuslen. Running low on supplies, Charles retreated hastily across the Svinesund and burned the bridges behind him. By 12 July 1716 all Swedish troops had been withdrawn from the area around Fredriksten.
In the Autumn of 1718 Charles once more attacked Norway, intending to first capture Halden to be able to sustain a siege of Akershus. The 1,400 strong garrison of Frederiksten fought ferociously to hold back the invasion, but suffered a severe setback when, on 8 December the forward fortification Fort Gyldenløve fell. Encouraged by their very hard-fought success the Swedish army intensified their efforts against the main fort. The Swedish trenches had almost reached the main fortification walls when on the evening of 11 December 1718, a bullet struck and killed Charles XII while he inspected the work. The death of the king effectively ended the attack on Fredriksten and the invasion was called off, leading to the conclusion of the war. A memorial is located in the park named in his memory where the Swedish king fell, just in front of the fortress.
In 1788 the fortress served as a staging area for a mock attack on Sweden during the Theater War. During The Napoleonic Wars the fortress was bombarded in 1814 but not captured. The advancing Swedish forces of Charles John passed it on their advance, leaving a force that tried to force its surrender, but the fortress and its commander kept the ground. It was turned over to Sweden after the Convention of Moss. The old fortress flag from 1814, taken by the Swedish troops and not returned to Norway until 1964, is preserved in the present day museum located inside the inner fortress.
After 1905 the fortress lost all military significance, but it still hosted various units. As of today the Norwegian defence logistics and administrative college is situated by the fortress. The fortress also hosts several museums and art exhibitions. During the summer season outdoor concerts are arranged with both classic and contemporary music.References:
The city walls of Avila were built in the 11th century to protect the citizens from the Moors. They have been well maintained throughout the centuries and are now a major tourist attraction as well as a UNESCO World Heritage Site. Visitors can walk around about half of the length of the walls.
The layout of the city is an even quadrilateral with a perimeter of 2,516 m. Its walls, which consist in part of stones already used in earlier constructions, have an average thickness of 3 m. Access to the city is afforded by nine gates of different periods; twin 20 m high towers, linked by a semi-circular arch, flank the oldest ones, Puerta de San Vicente and Puerta del Alcázar.