Trondheim was traditionally protected 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 was responsible for the new town plan of Trondheim after the great fire of April 18, 1681. 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 - Grüners and Frølichs redutt - but they are hardly visible today.
The main building featured in the picture 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.
During WWII the Nazis executed a number of Norwegian patriots at Kristiansten.
The fortress was the official place of execution of convicted and condemned traitors and war criminals following the legal purge in Norway after WWII. The notorious Henry Rinnan was executed here on February 1, 1947, and nine of his followers afterwards, eight of them on the same day in 1947.