In 1985, a bulldozer operator accidentally uncovered a pile of mangled skeletons in northern Spain. The remains of at least 338 individuals — including men, women and children — were found interwoven together alongside arrowheads, blades and axes.
The mass grave, which was dated to around 3000 B.C., was initially thought to be the product of an ancient massacre.
But now, after analyzing the tangled mass of bones, researchers believe many of the victims instead met their death in battle, according to a study published Nov. 2 in the journal Nature Scientific Reports.
The burial site, known as the San Juan ante Portam Latinam rockshelter, indicates a “more sophisticated and formalized way of warfare than previously appreciated in the European Neolithic record,” researchers said.
Researchers, who are affiliated with a university in Spain, made this conclusion after studying scores of healed and unhealed injuries present on the skeletons.
A total of 107 cranial injuries were found, most of which were on the top of skulls, indicating blunt-force trauma. The majority of these wounds, which appeared deliberate, were found on males.
Injuries on other body parts, including limbs, were also examined. Of all injuries found, 98% of unhealed wounds were found on male remains. Additionally, 81% of all healed injuries were found on male remains. Nearly half of all males at the site, 45%, exhibited wounds.
This suggests that “many males acted as combatants and eventually died in battle and raids.”
The men likely met their fate defending their settlement from raids, researchers said. Their remains likely were not buried all at once, but instead separately over time, creating “war layers.”
Their community was, at least for a while, successful in fending off attacks as evidence by the fact that there were survivors around to bury them.
“We think we are seeing the result of a regional inter-group conflict,” Teresa Fernández-Crespo, one of the study authors, told LiveScience. “Resource competition and social complexity could have been a source of tension, potentially escalating into lethal violence.”
Varying belief systems on the Iberian Peninsula may also have created cause for dispute, which could have resulted in warfare, researchers said.
Not everyone buried at the site may have been involved in battle, though, researchers said. It’s possible some of the individuals, particularly the very young and old, succumbed to nutritional deficiencies caused by food scarcity, among other factors.