The building of Akershus Castle and Fortress (Akershus festning) was commenced by the king Haakon V in 1299. It was built in order to protect the city from enemy attacks because the vicinity of the sea was of great importance to the majority of Norwegian commerce that was done by the sea route. Since the fortress was strategically important for the capital and Norway whoever controlled it, ruled the country.
During the reign of King Christian IV in the early 17th century the fortress was modernized and remodeled and it got the appearance of a renaissance castle.
The fortress was besieged every now and then in its history but never by a foreign enemy. However, it surrendered without combat to Nazi Germany in 1940 when the Norwegian government evacuated the capital during the unprovoked German assault on Denmark and Norway.
The fortress was liberated on 11 May 1945, when it was handed over to Terje Rollem on behalf of the Norwegian resistance movement. After the war, eight Norwegian traitors who had been tried for war crimes and sentenced to death were also executed at the fortress. Vidkun Quisling, self-proclaimed Prime Minister, was among one of those.
It’s interesting that during its history Akershus served as a prison, with a section known as The Slavery (Slaveriet) because the prisoners could be rented out for work in the city.
In addition to the castle, the Norwegian Armed Forces Museum and Norway’s Resistance Museum can be visited also. The Norwegian Ministry of Defence and Defence Staff Norway (armed forces headquarters) have a joint modern headquarters in the eastern part of Akershus Fortress.
Although still a military area, Akershus fortress is open to the public daily until 21:00 so make sure to walk around the castle while in Oslo!