Archeologists have newly discovered a Viking ringed fortress in Denmark, through an ingenious combination of old fashioned sleuthing and high-tech searching. The Danish Castle Center shares, “On fields at Vallø Estate, near Køge, [archeologists from The Danish Castle Centre and Aarhus University] have discovered traces of a massive Viking fortress built with heavy timbers and earthen embankments. The perfectly circular fortress is similar to the famous so-called ‘Trelleborg’ fortresses, which were built by King Harald Bluetooth around AD 980.”
|Søren M. Sindbæk and Nanna Holm|
by the burnt remains of a castle gate
Says Søren Sindbæk, professor of medieval archeology at Aarhus University, “The discovery has been a piece of detective work. We suspected that one fortress was ‘missing’ on the island of Zealand. The location at Vallø was quite the right setting in the landscape: in a place where the old main roads met and reached to Køke river valley, which in the Viking Age was a navigable fjord and one of Zealand’s best natural harbors. From there we worked our way forward step by step.”
This work started with Nanna Holm, of the Danish Castle Centre in Vordingborg, and her examination of precise laser measurements of the landscape. She noticed an almost imperceptible rise, clearly circular in shape, in the field. Holm explains, “It is a huge monument. The fortress measures 145m from side to side. We recognize the ‘Trelleborg’ fortresses by the precise circular shape of the ramparts and by the four massive gates that are oriented at the four corners of the compass. Our investigations show that the new fortress was perfectly circular and had sturdy timber all the front; we have so far examined two gates, and they agree exactly with the ‘Trelleborg’ plan.” The next step was calling in an expert in archeological geophysics: Helen Goodchild, from the University of York, England. Gizmodo reports, “Goodchild used a technique called gradiometry, which involves taking measurements of the Earth's magnetic field found in the soil at the site. By comparing variations from location to location, they were able to detect where humans had altered the Earth”.
In this way, archeologists were able to develop a “ghost map” that gave them a detailed view of the fortress layout — and showed them exactly where to put trenches for excavating. And what they’ve found so far is very exciting.
Holm says, “We can see that the gates were burned-down; in the north gate we found massive, charred oak posts.” And while the exact date of the site has yet to be determined, the researchers are certain that this is from the Viking age. “Fortresses constructed in this manner are only known from the Viking Age.”
As for why the fortress was burned and when, researchers don’t know — yet. “The burned wood of the gates will make it possible to determine the age by means of radiocarbon dating and dendrochronology,” Nanna Holm relates. “The samples have been sent, and we will be eager to hear the results. If we can establish exactly when the fortress was built, we may be able to understand the historic events of which the fortress was part.” She notes that the team is “eager to establish if the castle will turn out to be from the time of King Harald Bluetooth, like the previously known fortresses, or perhaps of a former king’s work. As a military fortification from the Viking Age, the monument may help to unravel the position of Zealand in relation to the oldest Danish kingdom.”
Article adapted from the following sources:
Danish Castle Center’s press release (in English) ... (Danish version)
Aarhus University article
Copehagen Post article