Once upon a time, back in the 9th century, there was a predominantly Danish Viking horde of militants that led a ferocious campaign across England. Unlike other Viking groups at the time, they didn’t just set out to raid, but to conquer, gain land, and seize political power too.
Referred to by the Christian Saxons as “heathens”, they briefly settled in Repton, Derbyshire, before disappearing into the weaves of time. It’s known that they fragmented shortly after their reign of terror, in 873-874 CE, but much about them remains enigmatic.
So – what happened to the so-called Great Army? A new study published in the journal Antiquity, led by the University of Bristol’s Department of Anthropology and Archaeology, has at least a partial answer. Reexamining a mass grave first discovered in the 1980s, it’s been confirmed that it dates back to the Viking era, and there’s a chance that it’s comprised of fallen members of the long-lost invaders from the north.
The Repton burial mound was analyzed shortly after its original excavation, and the bones of at least 264 men (80 percent) and women (20 percent), aged 18-45, were found beneath it. A double grave containing two heavily injured men, a Viking sword, and a Thor's hammer pendant, as well as a sacrificial grave containing the remains of four juveniles, were also found close by.
Rather uncomfortably, one unfortunate occupant of the double grave seemed to have had his severed penis replaced with a boar’s tusk to presumably accompany him into the afterlife.
Controversially, at the time, academics concluded that this mass grave was filled in over the course of several centuries. This was based on radiocarbon dating, which uses the decay of unstable carbon isotopes as a measure of time – and it revealed not a point in time, but an elongated chronology. Researchers at the time were baffled: sedimentological and archaeological evidence clearly demonstrated that the mass grave was made and filled in just once.
As time ticked on, it transpired that something may have thrown off the dating method, and Bristol bioarchaeologist Cat Jarman, a “Doctor of the Dead”, felt that a reassessment was required. As it turns out, that radiocarbon dating was thrown off by these mysterious fellows’ fish-heavy diet.
The basis of radiocarbon dating is that there is a constant level of carbon-14 in all living organisms, but this isn’t always the case. This isotope, which is continuously formed in the upper atmosphere as cosmic rays cascade into it, rains down from the sky, and is absorbed by plants and animals in a variety of ways.
Oceans, and anything living in them that assimilates carbon, are troublesome for researchers that use radiocarbon dating. Thanks to the way carbon-14 is distributed in those watery depths, a tree that’s the same age as a shellfish can actually appear to be 400 years younger.
Or, as Jarman phrased it to IFLScience: “If Ivar only ate fish and his mate Halfdan only ate sheep, and both were killed by Alfred on the same day, it would look like Ivar died 400 years before Halfdan.”
Those in the grave clearly ate a lot of seafood, and Jarman’s team suspected that threw off the original dating. Correcting for this, they found that the three main grave sites all date back to 872-885 CE, a relatively short period of time.
Significantly, this is a time directly associated with the Great Army’s base in this part of England. Could this grave have belonged to their war dead, perchance?
“We definitely can't prove that the mass grave is that of the Viking war dead. A radiocarbon date doesn't make you a Viking, and certainly not a warrior!” Jarman added.
“All we can prove is that they date to the right time, and with all the contextual evidence, it makes the conclusion far more likely than it was before. But we are by no means certain.”
Either way, this revelatory research means that we’re one step closer to tracing the final days of one of the most mysterious military forces in human history – and it’s all thanks to cosmic rays and fishy diets.