Bergenhus fortress contains buildings dating as far back as the 1240s,
as well as later constructions built as recently as World War II.
The extent of the enclosed area of today dates from the early 19th century.
In medieval times, the area of the present-day
Bergenhus Fortress was known as Holmen (The islet),
and contained the royal residence of Bergen,
as well as a cathedral and several churches,
the bishop's residence, and a dominican monastery.
Excavations have revealed foundations of buildings believed to date back to before 1100,
which might have been erected by king Olav Kyrre.
In the 13th century, until 1299, Bergen was the capital of Norway
and Holmen was thus the main seat of Norway's rulers.
It was first enclosed by stone walls in the 1240s.