Munkholmen: From Execution Ground to Benedictine Abbey

A short ferry ride from Trondheim's harbour brings you to Munkholmen, a flat green islet whose calm appearance hides one of the most layered histories of any place in the city. In the Viking age it was known as Nidarholm and used as an execution site: the heads of defeated chieftains were displayed here as warnings to seafarers entering the fjord. According to the sagas, the heads of Earl Håkon Sigurdsson and his slave Kark were among them around the year 995.

Soon after the Christianisation of Norway, the island became home to one of the country's first monasteries. Benedictine monks settled here around 1100, building a stone abbey that would survive — through fires, plague and political turmoil — until the Reformation swept the order away in 1537. Stones from the monastery were later reused when the Danish-Norwegian crown turned the island into a fortress.

From the 17th century onward, Munkholmen served as a state prison. Its most famous inmate was Peder Schumacher Griffenfeld, the Danish chancellor who fell from grace in 1676 and spent eighteen years in a cell here. By the 20th century the island had become a customs station, then a German anti-aircraft battery during the occupation, and finally what it is today: a popular swimming spot and open-air museum, where you can climb the old fortress walls and look back at Trondheim from the water.