History

The fortress installations did not see any action, however, during the wars between Denmark-Norway and Sweden in the seventeenth and eighteenth centuries. During the 1830s, proposals were discussed for the installations that came to be Oscarsborg Fortress the way we know the fortifications today.

The first construction phase was completed on 20 November 1848, and by December 1852 the rest of the cannons were installed in the main fort. The fortress was completed in 1853.

Named after King Oscar I
The fortress was named ”Oscarsborg” on the occasion of the visit by King Oscar I on Kaholmen on 23 August 1855. When the installations were completed, Oscarsborg was considered one of the most modern fortresses in Northern Europe, but this recognition was not to last for very long.

As early as in 1864 Oscarsborg Fortress was seen to be obsolete due to the rapid development of artillery technology. The original fortifications at Kaholmane were built as a protection against attacks from the sea. However, the fortress was easily circumnavigated, and could be taken from the land side. Consequently, Oscarsborg went through a second round of construction work in the 1890s.

Managed to sink the Blücher
A new torpedo battery was completed in 1901. On 9 April 1940, Oscarsborg Fortress passed its first, real test: the fort’s armaments managed to sink the German flagship, the Blücher. The brief respite this provided enabled the Norwegian Government to evacuate important people in Oslo. The King, Parliament and Government were thus able to flee and later organise the resistance from abroad.