When archaeologists from the National Museum discovered the foundations of a small building at Bispegård on the island of Samsø, they did not realise initially that they had uncovered the remains of a castle that had belonged to a medieval king.

The discovery of the castle of King Erik Menved, who reigned between 1287 and 1319, helps to fill in a hundred-year gap in the island’s history, according to Nils Engberg, head of the National Museum, and the person who headed the dig....