In the 1970s, archaeologists unearthed prehistoric human remains from a deep underground shaft in Somerset, England. The truth of what really happened to those men, women, and children, however, has only recently come to light.

Archaeologists in the UK and Europe have analyzed the Early Bronze Age remains of 37 individuals in England, uncovering evidence of a horrific massacre. Their findings, detailed in a study published today in the journal Antiquity, shed light on the largest known example of interpersonal violence in British prehistory and challenge the idea that Early Bronze Age Britain (roughly 2500 to 1200 BCE) was a period of relative peace.

The remains in question include over 3,000 human bones and bone fragments previously discovered in a 49.2-foot-deep (15-meter-deep) shaft at an archaeological site in Somerset known as Charterhouse Warren. The individuals were men, women, and children—potentially representing a community, according to the researchers—who were killed, butchered, and likely cannibalized before being tossed into the shaft.

Led by Rick Schulting from the University of Oxford, the archaeologists found evidence of blunt force trauma to the skull, fractures made at the time of death, and cut marks likely resulting from defleshing. The latter two findings specifically suggest intentionality behind the butchering and cannibalism, according to the study.

With regard to the cannibalism, the researchers ruled out funerary rituals and hunger as potential motivators. The death of the individuals was clearly violent, there is no evidence of a fight (so they were likely taken by surprise), and the presence of cattle bones in the same shaft indicate that there was no shortage of food at the time. What, then, could have driven this shocking act of prehistoric violence?

“Cannibalism may have been a way to ‘other’ the deceased,” the researchers wrote in an Antiquity statement emailed to Gizmodo. “By eating their flesh and mixing the bones in with faunal remains, the killers were likening their enemies to animals, thereby dehumanising them.”

This explanation, however, doesn’t clarify the motivation behind the violence as a whole. At the time, Britain wasn’t experiencing problematic climate change or other events that might have caused competition for resources, according to the study. There is also no known genetic evidence of ethnic conflict.

As a result, the researchers suggest that the conflict may have been caused by social factors and ultimately triggered by offenses such as theft and/or insults. Perhaps the plague—revealed in the infected teeth of two children by previous research—may have also worsened pre-existing tensions.

“Ultimately, the findings paint a picture of a prehistoric people for whom perceived slights and cycles of revenge could result in disproportionally violent actions. This situation is, unfortunately, familiar from more recent times,” they wrote.

Although direct evidence of violent conflict in Britain between 2500 and 1500 BCE is scarce, the scene of this massacre undoubtedly challenges the suggestion that the time period may have been relatively peaceful.

“It paints a considerably darker picture of the period than many would have expected,” Schulting explained. “Charterhouse Warren is one of those rare archaeological sites that challenges the way we think about the past,” he added. “That it is unlikely to have been a one-off event makes it even more important that its story is told,” he added.

“At this stage, our investigation has raised as many questions as it has answered. Work is ongoing to shed more light on this decidedly dark episode in British prehistory,” the researchers concluded in the study.

While there’s nothing we can do about obscure prehistoric atrocities, perhaps we can learn not just from history but from prehistory to stop our own revenge cycles from spiraling out of control more than they already have.