Victims of a tsunami or human sacrifice: what happened to 20 Celts 2,000 years ago?

The mysterious discovery of human remains near the ruins of a bridge in Switzerland's Three Lakes region has sparked curiosity among archaeologists. In an effort to gain insights into the region's Celtic heritage, experts have embarked on an extensive study to unravel the story behind the finding. The recovered items include a mix of bones, skulls, and wooden beams, found on the riverbed during the Thielle Canal renovations in 1965.

Collaborating on an international project led by the University of Bern and the Eurac Research Institute for Mummy Studies in Bolzano, researchers from various disciplines such as archaeology, anthropology, biochemistry, thanatology, and genetics have meticulously investigated the case. Their comprehensive study findings have been published in the journal Scientific Reports.

The primary focus of this project is to shed light on the Celts and improve our understanding of their presence in Switzerland and northern Italy. While much of Celtic culture is documented orally and limited written sources exist, most of the available information comes from Julius Caesar's accounts, which are biased as a military adversary.

With an aim to amplify the voices of the untold from the archaeological findings, Zita Laffranchi, a postdoctoral fellow from the Institute of Forensic Medicine at the University of Bern, together with her team, embarked on a bioarchaeological investigation. Radiocarbon dating, isotopic analysis, and paleogenetics were among the methodologies employed to reconstruct the ancient drama that unfolded in Cornaux/Les Sauges.

The Celtic bridge and the discovered skeletons have sparked debates and controversies, with two prevalent theories being deliberated. Some argue that a sudden flood or tsunami caused the wooden structure to collapse, while others speculate that the corpses were victims of human sacrifice - a ritual often related to water in Celtic practice.

Extensive examination of the skeletons, along with their unique preservation and the presence of brain fragments in a few skulls, suggests that sediment promptly covered the corpses after their demise. Multiple bone lesions and the absence of intentional or sharp-object-related injuries indicate a forceful impact. Additionally, the entanglement of bones with wooden fragments further supports the notion of an accidental event, potentially triggered by a tsunami.

The scrutiny of bones and teeth included chemical analysis, radiocarbon dating, and paleogenetic analysis. Through this meticulous approach, the research team identified a group of at least 20 individuals without evident familial connections. Among them were a young girl, two children, and 17 predominantly young adults, with 15 likely being males. The disproportionate representation of young adult males suggests various scenarios, such as this group comprising prisoners, slaves, merchants, or soldiers. Due to ambiguity in some radiocarbon dates, it remains uncertain whether the deaths occurred simultaneously or during the bridge's destruction.

In conclusion, the exact sequence of events surrounding the Celtic bridge at Cornaux/Les Sauges continues to remain shrouded in mystery. Marco Milella, a researcher from the University of Bern and co-leader of the project, suggests that this bridge possibly served as a sacrificial site, where some corpses predated the accidental incident. The collaborative research not only emphasizes the importance of valuing individual life stories but also enriches our understanding of cultural and biological heritage within the broader population.

The Three Lakes region held significant significance for the Celts, particularly the Helvetians. This study, which pioneers the application of paleogenomics in analyzing Swiss Celtic individuals, provides solid evidence of their genetic affinity to other populations during the Iron Age. Some lineage connections identified in Cornaux are also found in regions like Britain, the Czech Republic, Spain, and central Italy. Isotopic analyses suggest a blend of individuals raised in both the Three Lakes region and the Alps, highlighting the area's lively crossroads and the Celts' mobility during that time.