Around 4,900 years ago, on the Danish island of Bornholm, a peculiar form of ritual sacrifice took place—hundreds of stones inscribed with sun and agricultural motifs were offered in what would now be described as a response to extraordinary environmental phenomena. This discovery has been linked to a large volcanic eruption that caused a dramatic climatic shift and rendered the sun invisible for extended periods in Northern Europe.
Although written records do not exist from the Neolithic period, the archaeological team from the University of Copenhagen and their international colleagues have found important clues. In particular, climate scientists from the Niels Bohr Institute analyzed ice core samples from glaciers and proved that, indeed, a massive volcanic eruption took place around 2,900 BC, consistent with the climatic disruptions recorded in the ancient site of Vasagård on Bornholm. These findings are published in Antiquity and shed light on the intertwined effects of environmental catastrophe and human response at a time of deep agricultural dependence.
Volcanic Eruptions and Their Aftermath
The relationship between volcanic eruptions and climate impacts has long been known. Throughout history, eruptions that launch large quantities of sulfur into the atmosphere can have widespread consequences on the global climate, including crop failures, famine, and disease. In one notable event in 43 BC, an eruption in Alaska ejected vast amounts of sulfur into the stratosphere, creating a chilling effect that led to harvest failures across Mediterranean Europe. The resulting crop shortages triggered famine and widespread sickness, as written records from Ancient Greece and Rome attest.
However, the catastrophe facing the Neolithic people of Northern Europe during the 3rd millennium BC, though similar, did not leave written sources to explain its cause. The recent climate research from the Niels Bohr Institute points to an eruption that took place about 2,900 BC, possibly linked to the darkened skies and cooler temperatures observed in ice cores from this period. The resulting environmental shifts—more cold, diminished sunlight, and delayed growing seasons—would have deeply disrupted agricultural societies that depended heavily on the cyclical rhythms of planting and harvesting. For the people of Northern Europe, who were still in the Neolithic era, this would have been catastrophic.
The people of Bornholm, situated in the Baltic Sea, were not immune to these climate impacts. Their livelihood, built on agricultural practices like wheat and barley cultivation, depended on seasonal rhythms that the cooling event severely affected. Archaeologists have speculated that this volcanic winter, as it has come to be known in historical study, forced human societies to look for ways to mitigate the fallout from such significant climatic disturbances.
The Neolithic Response: The Sun Stones
Neolithic agricultural communities, especially in Northern Europe, had strong cultural and religious links to the sun, which they saw as essential for the fertility of the land. They understood that without the warmth and the cycle of seasons, their crops would not grow, and without successful harvests, their communities could not survive. One of the most intriguing discoveries from this period was the “sun stones” from the site of Vasagård on Bornholm. These sun stones, unlike regular stones, were uniquely shaped and often decorated with symbols that closely resemble solar motifs. In their most symbolic form, these flat pieces of shale—sometimes engraved with sun symbols—were probably used as ritual sacrifices.
The practice of stone offerings and sacrifices was not unusual in the ancient world. Such acts were seen as a way of communicating with deities or powers thought to control aspects of the natural world, like the sun, the crops, and the seasons. It is believed that these stones, offered to ensure the return of the sun’s warmth or to appease whatever gods or forces might have caused its temporary disappearance, may have been part of a larger social and religious ritual aimed at protecting the community from the harsh environmental conditions.
Dr. Rune Iversen, an archaeologist from the University of Copenhagen and part of the excavations at the site of Vasagård, highlights the importance of this discovery: “We have known for a long time that the sun was the focal point for the early agricultural cultures in Northern Europe. They depended on it to bring in their harvest, and if the sun almost disappeared for a period due to mist in the stratosphere, it would have been frightening. It would have undermined everything they held dear—food, survival, and the continued stability of their society.”
At the Vasagård site, archaeologists uncovered several hundred sun stones, found in large quantities at the West site of the Neolithic settlement. These stones were not placed randomly; they were found in ditches of a causewayed enclosure—ritualized areas where sacrifices and feasts likely took place. Other artifacts found in the ditches included animal bones, broken clay vessels, and flint objects, all evidence of food-based rituals and sacrificial acts. The enclosures, which are believed to have been ritualistic in nature, were subsequently sealed up. This indicates a potential closure of the rite, perhaps signaling the end of a climatic ordeal or a symbolic return to normalcy after the eruption’s effects had diminished.
What the Evidence Tells Us
Dr. Iversen and his team suspect there is a direct connection between these sun stones, the volcanic eruption, and the ensuing environmental change. “It seems reasonable to believe that Neolithic people on Bornholm wanted to protect themselves from the drastic climate change,” Dr. Iversen says. “Sacrificing these stones—objects imbued with sun-related symbolism—would have been seen as an act to ensure the sun’s return, or at the very least, to thank whatever powers were responsible for ending the darkened skies.”
Interestingly, the people of this era were also facing new health challenges. DNA studies of human bones from the same period reveal evidence of a widespread plague, further compounding the difficulties caused by climate change. During the same period of extreme climatic fluctuations, the Neolithic world saw the rise of disease as well as changing social and cultural patterns, highlighting how crisis can spur drastic societal shifts.
A Changing Culture: The End of the Funnel Beaker Culture
The destruction of agricultural yields and the spread of disease would have undoubtedly shaken the social structure of the Neolithic communities in the North. In particular, the “Funnel Beaker Culture,” one of the dominant cultures of the period, began to show signs of decay. Its distinct pottery style and monumental burial structures began to disappear around 2,900 BC, signaling the collapse of a long-standing cultural framework.
The archaeological evidence from the Vasagård site on Bornholm shows that significant changes took place within the layout of the settlement following the ritual sacrifice of the sun stones. Instead of the ditches that had marked earlier periods, new construction took place in the form of rows of palisades and circular cult houses. These changes, while still part of the broader Neolithic tradition, suggest that something had shifted in the community, a shift potentially influenced by both environmental factors and social upheavals brought on by climate stress, disease, and the collapse of long-standing practices.
As Dr. Iversen concludes, “We do not yet know why the people of this period chose to abandon their older ceremonial practices, but it is reasonable to believe that their experience of extreme climate fluctuations played an important role.”
Conclusion: A Complex Web of Crisis, Belief, and Adaptation
The discovery of sun stones from Bornholm offers an intriguing window into how Neolithic peoples coped with the challenges of climate change. Their ritual acts, likely driven by fear, uncertainty, and the loss of control over nature, reveal just how central agricultural prosperity and the cycles of the sun were to their survival. The combined effects of volcanic eruptions, disease, and shifting cultural practices must have created an atmosphere of fear and uncertainty—factors that led to dramatic rituals of appeasement and, ultimately, to a significant change in social and cultural practices. These findings, which tie together the history of an ancient community with modern climate research, demonstrate the intertwined relationship between environmental changes and human response. While ancient peoples lacked the scientific knowledge we possess today, their actions remind us of the profound impact that environmental shifts have on societies—and how these impacts, even thousands of years ago, could shape the future trajectory of human culture and civilization.
Reference: Sun stones and the darkened sun: Neolithic miniature art from the island of Bornholm, Denmark. Antiquity. DOI: 10.15184/aqy.2024.217