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Laser Tech Reveals 1,000-Year-Old Viking Ring Fortress in Denmark

Laser Tech Reveals 1,000-Year-Old Viking Ring Fortress in Denmark

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With the help of laser technology, archaeologists have managed to discover a perfectly circular ring fortress in Borgring, Denmark. It dates back to 975-980 AD, and experts suggest that it was constructed during the reign of King Harald Bluetooth.

Borgring Fortress First to be Discovered in Denmark Since 1953

IBTimes UK reports that the impressive Borgring fortress is the first to be discovered in Denmark since 1953. What has amazed experts the most about this massive fortress is how it appears to be in a very precise circular shape, measuring almost 150 meters in diameter. The building is one of the Trelleborg-type fortresses that have a characteristic circular shape and internal design. The earthworks, houses and other structures are carefully positioned within the fortress and four gates are positioned around the perimeter at cardinal points.

“The Borgring fortress had been tentatively identified in the 1970s, but the technology was lacking then to verify whether it really was a Trelleborg-type fortress,” study author Søren Michael Sindbæk of Aarhus University, told IBTimes UK. And continued, “That is the most beautiful aspect of our results – the suspicion that this could have been a fortress was raised by a very beautiful map made in 1970 that was the best survey method you had in those days. But it was impossible to prove it in those days."

The Trelleborg ring fortress

The Trelleborg ring fortress (CC by SA 3.0)

Airborne Laser Scanning Helps Archaeologists to Examine the Fortress 

With the help of advanced modern technology such as LiDAR – airborne laser scanning – Sindbæk and his colleagues managed to estimate significant differences at ground-level indicating the presence of the ring fortress as IBTimes UK reports. Before its demolition, the Borgring fortress was created from wood with earth-and-turf ramparts. The fortress contained two streets with that intersected each other to form a cross shape. The streets were most likely paved with timber, with four vast wooden structures within the fortress.

The importance of the discovery consists of the fact that there have only been five confirmed Trelleborg fortresses discovered in Denmark until now. They were all constructed in a short period of time between 975 and 980 AD, during the reign of Harald Bluetooth, a 10 th century king who Christianized both Denmark and Norway.

Architectural Achievements of the Vikings

In 2014, archaeologists identified another impressive fortress through laser scan, which had been initially discovered in 1875  – a ring-shaped Viking fortress on the Danish island of Zealand – which historians suggested could have been used to train warriors before launching an invasion of England. As previously reported in an Ancient Origins article, even though the Vikings carry a reputation as brutish invaders, the latest finding shows that they were also accomplished builders. Coincidentally, the research team that made that discovery in 2014, suggested that the fortress dated back to the reign of Harald Bluetooth as well.

Reconstruction of a Viking ring fortress. Unknown artist

Reconstruction of a Viking ring fortress. Unknown artist

Massive, Circular Constructions

The obvious similarity between all these buildings that were constructed during Harald Bluetooth’s reign is that they are all massive and circular constructions typically between 140 to 250 meters in diameter. "They posed a real enigma about the Viking Age when they were first discovered. The Vikings were perceived to be a society of local petty kings competing over power," Sindbæk tells IBTimes UK.  And adds, "They are related to a period of exceptional expression of kingship. The question is whether that means we need a complete reassessment of Viking society, or whether we should just be revisiting evidence from this particular period," Sindbæk says, wondering how such vast and costly constructions appeared in Denmark all of a sudden around the year 975.

Enemies Led to the Construction of the Buildings 

The fact that these large fortresses were constructed within just five years makes Sindbæk speculate that the Vikings were facing dangerous external enemies coming from the German and Slavic lands. “If we look at the 970s and 980s, it's exactly a time where every authority bordering on this empire is in a high state of emergency. There is a military power which is unprecedented and isn't repeated again for several generations," Sindbæk told IBTimes UK.

Interestingly, after the German emperor died in the 980s, the construction of massive and expensive buildings in Denmark stopped suddenly, a fact that appears to justify Sindbæk’s speculations, who closes his mini-interview by pointing out the historical value and importance of these fortresses by stating to IBTimes UK, "We have barely any other similar fortresses in Norway or Sweden, and in Denmark there are no other very large fortresses of any kind. So they are very special. Because of the dates it seems that they coincide with a very unique military situation."

By Theodoros Karasavvas

Theodoros Karasavvas's picture


Theodoros Karasavvas, J.D.-M.A. has a cum laude degree in Law from the University of Athens, a Masters Degree in Legal History from the University of Pisa, and a First Certificate in English from Cambridge University. When called upon to do... Read More

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