Researchers have discovered evidence of a previously unknown Iron Age fortress beneath the ruins of Lilleborg Castle on Bornholm. This groundbreaking finding, announced in a press release by the National Museum of Denmark, challenges previous assumptions about the site’s history.

Laurine Albris, the research leader for the project, confirmed the existence of the Iron Age fortress, which had been concealed beneath the medieval ruins. The discovery has prompted new excavations to uncover more details about this ancient structure.

The initial clue came during a 2010 renovation of Lilleborg when the Bornholm Museum examined a layer of grain, ash, and charcoal located deep beneath the castle ruin. While initially attributed to a 13th-century fire, recent carbon dating has revealed a much earlier origin.

The new carbon samples date the remains to the late 5th century, approximately 700 years earlier than originally thought, indicating the presence of an Iron Age castle.

Researchers are now planning further excavations to investigate the newly discovered Iron Age fortress. These excavations aim to determine the number of times the castle may have been burned and to find additional traces of events that occurred at Lilleborg during the Iron Age.

Lilleborg, situated in Almindingen Forest in the center of Bornholm, was constructed in the 12th century and likely destroyed in the mid-13th century.