The naval fort Prövestenen traces its history back to 1713, when a barge of the same name was lowered as a reinforced artificial island to provide emergency shelter for the fleet. The fort that exists today is built in 1859-63.
The fort is erected on an artificial island of boulders. The artillery was located in an open facility divided by five concrete-cast crossers with ammunition depots and crew rooms.
The facility had floodlights. There was a smaller port facility in connection with the facility.
The fort is part of the inner naval defence line and, together with Strickers Battery, the Mellemfort, the Lynetten and the Trekroner.
It was supposed to keep enemy ships at a distance from Copenhagen and in particular prevent him from entering the Kongedybet – the area between the island of Saltholm and Zealand and thus the entrance to the Copenhagen Harbor.
The fort has been rerarmed several times.
Around World War I, at the last reinforcement, the armament consisted of
16 pcs. of 17 cm steel cannons,
6 pcs. of 29 cm iron cannons
8 pcs. of 47 mm cannons, three of which were for air defense. In addition,
1 75 mm cannon
2 pcs. of machineguns
2 pcs. of 90 cm floodlights.
This was later reduced to
12 pcs. of 17 cm guns,
1 75 mm. gun
3 pcs. of 47 mm. guns.
The fort was abandoned in 1922.
The area has been storage of gasoline since mid 1930s at is normally not accessible.