Kalø

Kalø Castle occupied an island in a sheltered bay of eastern Jutland, linked to the mainland by a paved causeway. Erik Menved began the fortress in 1313 after suppressing a Jutland revolt, using it to impose royal authority. Although his successor promised its demolition in 1320, the extent of that destruction remains uncertain. Building probably resumed after Valdemar Atterdag took the throne in 1340. Queen Margrethe redeemed the castle from its pledge to the bishop of Aarhus in 1407.

The fortress became the centre of a royal fief, combining administration with imprisonment. Gustav Vasa was held there in 1518–1519 before escaping to Lübeck; he later became king of Sweden. As its military value declined, Kalø continued to serve the fief until the reforms following the introduction of absolutism. The fief ended in 1661. In 1672 Ulrik Frederik Gyldenløve dismantled the castle, shipping useful material to Copenhagen for the palace now called Charlottenborg.