The fortress was built after the great fire of 1681, and offers fantastic views of the city and its surroundings. During WWII the Nazi authorities executed members of the Norwegian resistance here. The fortress is open to the public, and you’ll find an open café inside the fortress walls all year.
The main building featured in the picture above is the defensive tower – Donjonen – with artillery, quartering and stores was the centre of the defences. After decommissioning in 1816 it was location of the fire watch, and since 1997 as a museum.
Trondheim was traditionally protected with fortifications by the river Nidelven and Skansen, but the city was vulnerable to attack from the east. The Fortress was therefore put on a hill to protect the city centre and control the area from Ila to Lade. General Johan Caspar von Cicignon, who was chief inspector of kuks fortifications, was responsible for the new town plan of Trondheim after the great fire of 18 April 1681. He also made the plans for the construction of Kristiansten Fortress.
The fortress was built during the period from 1682 to 1684 and strengthened to a complete defence fortification in 1691 by building an advanced post Kristiandsands bastion in the east and in 1695 with the now vanished Møllenberg skanse by the river Nidelven. These fortifications were encircled by a continuous palisade and thereby connected to the fortified city. In 1750 the fortress was modernized with new bastions and casemates to protect against mortar artillery. Two new isolated defensive works were also built to the east – Grüner’s and Frølich’s redoubts – but they are hardly visible today.