More than three millennia ago, on the edge of a river valley in what is now northeast Germany, two large armies clashed in battle. Now, researchers are piecing together clues from ancient arrowheads to uncover a more detailed picture of Europe’s earliest known large-scale conflict, reshaping our understanding of Bronze Age warfare.

The battlefield in the Tollense Valley was first uncovered in 1996 by an amateur archaeologist. Excavations at the site have revealed over 12,500 bones belonging to at least 150 skeletal remains, many still bearing the marks of violent injuries. These warriors fought in a massive battle around 1250 BCE.

Alongside the bones, archaeologists found an array of ancient weaponry, including swords, wooden clubs, and most importantly, bronze and flint arrowheads — some still embedded in the bones of the fallen.

But until recently, much about this conflict — who fought, where they came from, and why — remained a mystery. Now, new research into the arrowheads found at the site is shedding light on the scale and scope of this violent encounter, offering a more detailed picture of early warfare in Europe.

Arrowheads as “Smoking Guns”

For decades, the origins and identities of these warriors remained a mystery. Were they locals defending their territory, or invaders from afar? A new study, published in Antiquity, sheds light on this question by analyzing the arrowheads found at the site. Leif Inselmann, lead author and a researcher at the Free University of Berlin, calls the arrowheads a “smoking gun.” Much like a murder weapon in a modern investigation, these artifacts offer clues about who was involved in the battle and where they came from.

By comparing the 54 arrowheads from Tollense with over 4,700 Bronze Age examples from across Central Europe, Inselmann and his team identified key differences in their shapes and design. Many arrowheads matched styles common in the region of Mecklenburg-Western Pomerania, where the Tollense Valley is located. However, others bore distinct characteristics linked to regions far to the south — modern-day Bavaria and Moravia. This suggests that some of the warriors in this battle were not local to the area.

Rather than being imported weapons, the unique design of these arrowheads implies that warriors traveled hundreds of miles to fight.

Of course, other weapons were used. While no swords have been found at the site, skulls recovered from the battlefield show cut marks that indicate the use of swords, along with wooden clubs and other blunt weapons.

Violence in Bronze Age Europe

The discovery of these southern arrowheads challenges earlier theories that the conflict was purely local. Previous studies of isotopic data from bones at the site hinted that foreign warriors might have been involved. But the arrowhead analysis strengthens the case for interregional conflict. So, it’s possible that these southern fighters were part of a warlord’s retinue. Or, perhaps, they were mercenaries engaged in a larger political struggle.

“This new information has considerably changed the image of the Bronze Age, which was not as peaceful as believed before,” said Thomas Terberger, coauthor of the study and professor of archaeology at the University of Göttingen.

The 13th century BC was a period of major transformation across Europe. The rise of fortified settlements, the professionalization of warriors, and the construction of hillforts signaled a shift towards more organized and large-scale warfare. Tollense is just one example of such developments. And it wasn’t just a small skirmish, but rather a significant conflict involving multiple competing regional forces.

While other Bronze Age archaeological sites have revealed evidence of mass killings — sometimes even entire communities slaughtered —this is the first time the demographics of the dead indicate they were likely warriors rather than civilians. The battle suggests a higher level of social organization, with large groups of men possibly organized into armies.

The Spark of War

What sparked this bloody conflict remains unclear. One theory is that it was a battle for control of a vital trade route. A causeway crossing the Tollense River had been built some 500 years before the battle, possibly serving as a bottleneck for regional trade. “Control of this bottleneck situation could well have been an important reason for the conflict,” Terberger told CNN in an interview.

However, the researchers remain cautious about this theory. Despite the importance of trade, there are no clear signs of nearby sources of wealth. For example, metal or salt mines, often tied to violent conflicts, are absent from the region.

The remains of the warriors — young men aged 20 to 40, with some showing signs of having fought in previous battles — point to a highly organized and possibly professional fighting force. Some may have been mounted on horseback, as evidenced by the remains of at least five horses found at the site.

While the precise details of what led to the battle are still unknown, the scale of the conflict, with potentially more than 2,000 combatants, represents a level of warfare previously unseen in Europe’s Bronze Age. This challenges the long-held belief that Bronze Age societies were relatively peaceful, with trade driving much of their cultural development.

As excavations continue, researchers expect to uncover more about the lives — and deaths — of the people who fought here. The discoveries at Tollense Valley are helping to reshape our understanding of the Bronze Age, revealing that large-scale violence was a significant part of life in this period of European history.

“The Tollense Valley conflict dates to a time of major changes,” concludes Inselmann, now at the Freie Universität Berlin. “This raises questions about the organization of such violent conflicts. Were the Bronze Age warriors organized as a tribal coalition, the retinue or mercenaries of a charismatic leader — a kind of ‘warlord,’ or even the army of an early kingdom?”