Incredible Viking Ring Fortress Discovered In Denmark

The fortress probably looked a lot like this reconstructed Viking battlement in Sweden. Antony McAulay/Shutterstock

We tend to think of the Vikings as a transient culture, riding the high seas, pillaging villages, and then making off with the spoils. Yet more and more evidence is being discovered that fundamentally changes this image of the Norse seafarers, with fortresses discovered in Denmark suggesting that there was far more to the Vikings than many have previously appreciated.

Archaeologists have now described an impressive fortress in the journal Antiquity, built in a perfectly circular arrangement, that they have dated to having been built by the infamous Viking and Danish King Harald ‘Bluetooth’ Gormsson. This is now the fifth such castle discovered in Denmark since the 1930s and has shifted the general opinion of the Vikings, showing that they during the Middle Ages they formed complex, technologically advanced settlements.


This latest fortress, called Borgring, has been found just south of Copenhagen on the island of Zealand. While there is nothing much to see at ground level apart from a few mounds, as the land has been plowed and tilled for centuries, aerial surveys using LIDAR have clearly shown the remains of the ring fortress in incredible detail. Using this as a template, the researchers have been able to uncover a whole host of amazing artifacts revealing just how complex this structure was, and what the culture and society at the time must have been like.

The LIDAR clearly shows the ancient fortress. Goodchild et al. 2017

The perfect circular arrangement of the ramparts, built from earth and timber and 144 meters in diameter, shows an astonishing skill, particularly as it was not strictly necessary. The researchers have uncovered paved wooden roads and four gates, as well as jewelry and an amazingly well-preserved carpenter’s box complete with planes and chisels. Tree rings from the timbers date the fortifications to between 970 and 980 CE, during the reign of Harald Bluetooth.

The evidence suggests, however, that the fortress met a brutal end. The archaeologists found signs that the structure seems to have been attacked, with two of the gates having been significantly burned. Whoever was behind the sacking of the fortification is still not known, but Harald Bluetooth did not ascend to the throne without making at least some enemies.

The structure probably contained a significant settlement. Goodchild et al. 2017

The researchers suggest that an old rivalry with Swedish Vikings may have had some bearings, as the fortress is located within close proximity of the southern tip of Sweden. Not only that, but just decades later there are reports that the Danish and Swedish battled it out on the frigid Baltic Sea that separates the two nations, not far from the pillaged stronghold.


Currently, this is purely speculation, but perhaps with time and further excavations, more could be gleaned about the fate of this once impressive fortification.


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  • Sweden,

  • denmark,

  • viking,

  • Middle Ages,

  • castle,

  • fortress,

  • harald bluetooth,

  • ancient ancestors