Researchers discovered a previously unknown Viking fortress that could help provide insight into Denmark's history.
The circular fortress was discovered in a field in the diocese of Vallø, west of Køge. It is similar to the "Trelleborg" fortresses built by King Harald Bluetooth in about 980 AD, Aarhus University reported.
"This is the first time for more than 60 years that a new Viking ringed fortress has been discovered in Denmark," said Nanna Holm, an archaeologist and curator at the Danish Castle Centre. "The discovery of the new Viking fortress is a unique opportunity to learn more about the battles and conflicts of the Vikings, and gives us a new chance to study the most famous of our Viking monuments."
The finding was made possible by a precise laser measurement of the local landscape. The measurements revealed a mound in the field that had a circular outline, suggesting the presence of an ancient ruin.
"Measuring small variations in the magnetic field of the soil enables you to identify old pits or embankments without destroying them. The technique gave us a surprisingly detailed image of the fortress in no more than a few days. So we knew exactly where to dig the excavation trenches with a view to learning as much as possible about the fortress," said Søren Sindbæk, a professor of medieval archaeology at Aarhus University.
The researchers believe the fortress was a military facility dating back to the Viking Age. A clue was the burnt timber at the gates that allowed the researchers to perform radiocarbon dating and dendrochronology. The samples are still under analysis and will be returned within a few weeks.
"We can't wait to find out whether the fortress dates back to the time of Harald Bluetooth, or whether it was built by a previous king. A military fortification from the Viking Age may shed more light on the links between Zealand, ancient Denmark and the Jelling dynasty - as well as teaching us more about the period during which Denmark became Denmark," Holm said.
The fortress is still largely unexcavated, but the researchers hope to change this in the near future.
"The excavation has already confirmed far more than we dared to hope, but we don't know the whole story yet. The next question is whether any big buildings were built inside the fortress, as they were in the Trelleborg fortresses. You also have to ask yourself if there are any more hidden ringed fortresses out there," Sindbæk concluded.
