About 6,200 years ago, a group of at least 41 men, women, and children were brutally murdered before being thrown into a mass grave in what is now eastern Croatia. Initially, the archaeologists who uncovered the tomb in 2007 wondered if the victims were a whole interrelated community focused on execution. But a new analysis appears in the journal PLOS ONE—Including the largest genetic study of an early massacre to date – reveals that the victims were mostly unrelated. This surprising discovery raises more questions than it answers: Why were these individuals killed, and who killed them?
“This is the one million dollar demand,” said the study’s lead author, Mario Novak, an archaeologist from the Institute for Anthropological Research in Zagreb, Croatia. “We just do not know.” And unless there is clear archaeological evidence in the area, he adds, “I do not think we will ever find it.”
Graves under the garage
The ancient massacre was accidentally discovered during the construction of a garage in the Croatian village of Potočani. The tomb – seven meters wide and three meters deep – contains the skeletal remains of at least 41 people, some of whom are still articulated, some broken into pieces.
Archaeologists from the University of Zagreb’s archaeological team that was in the area at the time were called in, and they assumed that the remains belonged to the victims of modern warfare, perhaps from World War II or the conflict from the Balkans in the 1990s. But an initial examination showed no bullets or uniforms, and teeth showed no evidence of modern fillings.
Additional excavations have yielded fragments of ancient pottery, and radiocarbon dating of three human bones has revealed that the site was 6,200 years old. Based on the date and place and the pottery found, researchers concluded that the victims belonged to the Lasinja culture.
Very little is known about these peoples, says Novak, and only one other cemetery in Croatia associated with the Lasinja culture has been excavated. “It is one of the least studied prehistoric cultural complexes in the region,” he says. Previous work on the other cemetery indicates that they were herdsmen who moved with their livestock to different grazing areas depending on the season. They also mined copper to make tools.
In bio-archaeological work, 21 men and 20 women were identified, including adults of 50, adolescents and children, perhaps just two years old. It quickly became clear that they were not dead to the natural causes.
Three adult males, four adult females and six children were found with damage to the sides or back of their skulls. These fatal injuries – blunt trauma fractures, stab and stab wounds and cuts – were carried out using weapons or tools, perhaps stone axes and sticks or metal instruments. The murder weapons were not found at the scene, but it appears that these injuries were inflicted in time during a single incident.
Particularly grim was the fact that some skulls sustained multiple injuries. “For most people, one hold was enough,” Novak says. ‘But we have two or three individuals with four injuries on the skulls. It was kind of too much or madness. ‘
A history of violence
What was clear though was that this massacre was not the result of warfare: mass graves as a result of fighting mostly contained teenagers or adult men, not women and children. There were also no facial injuries or wounds to the victims’ forearms, which happens when people instinctively raise their arms to stop incoming assaults. These people were probably immobilized, perhaps hunched over or kneeling, with their hands tied.
“They did not defend themselves,” Novak said. “I would say it was a pre-planned mass execution.”
The massacre of Potočani is not the first in European prehistory – another mass grave from a little further back in time in Halberstadt, Germany, for example, was filled with victims killed by battered blows to the back of the head.
“The cranial injuries look just like other carnages I’ve worked on – unfortunately also very much in place and age group,” says Trish Biers, an osteologist and paleopathologist at the University of Cambridge who was not involved in the work. .
Hoping to find out more about Potočani’s victims, the research team uncovered the DNA of 38 individuals from the site. The results showed that everyone had the same genetic ancestry: along with a small generation of hunters from collectors’ associations in Western Europe, these people’s predecessors came from Anatolia, which is now a large part of Turkey. They originally brought agriculture to Europe about 8,500 years ago. A few millennia later, some of their descendants wandered around the Balkans with their livestock.
Although some of the deceased were closely related – the DNA analysis, for example, identified a man, his two daughters and his nephew – 70 percent of the individuals were not. One possible implication is that these victims were part of a larger community consisting of many families.
The ghost threat
Biers says that her work on archaeological sites in both North and South America shows that people who were not necessarily genetically closely related had social kinship groups determined by their occupations, such as fishermen, farmers or artisans.
However, social relationships are something “we can not see from genetics”, says Christiana Scheib, an archaeologist who specializes in ancient DNA at the University of Cambridge and was not involved in the work. Ideally, non-slaughter graves from the area give an idea of what the normal distribution of the dead, genetically as well as the kinship groups, would have been. But so far the Potočani mass grave stands alone; no adjoining settlement was found.
The mystery is that the killers themselves know nothing. “We have no trace of the people who committed this cruelty,” Novak said. The offenders may have belonged to a rival group, whether they came from elsewhere or closer to home. The killers were possibly even from the same population as the victims.
It is also impossible to speculate about a motive. Other massacres and episodes of massage violence from European prehistory are attributed to antagonizing factors such as xenophobia or climate change, when droughts caused resource shortages and consequent violence. But at Potočani “we have no indication of any climate change during this period,” says Novak.
The only thing that is very clear is that this fundamental dark human behavior has been going on for thousands of years. Mass murders have been going on around the world for at least 13,000 years. Although legal systems were eventually instituted, and society in general became more orderly and less violent, massacres on a massive scale became easier over time. The ax was replaced by the rifle; warring tribes were replaced by state-aided genocide.
If sites like the one in Potočani tell us anything, it’s that people have not changed in the last 10,000 years, ‘says Novak. “If they did, they changed for the worse.”