Akershus Fortress or Akershus Castle is a medieval castle that was built to protect and provide a royal residence for Oslo, the capital of Norway.

The fortress was first used in battle in 1308.

Work started on the castle around the late 1290s under King Haakon V.

After construction of the castle was finished around 1300, Haakon V gradually started to use the castle as a residential palace .

Iron Chair sculptures, just outside the Akershus Fortress, Oslo, Norway.

Long view of Oslo city from akershus.

The fortress has successfully survived many sieges, primarily by Swedish forces.

Akershus Fortress houses the Royal Mausoleum.

The castle has also been used as a military base, and is today its a museum.