A dramatic mystery surrounds the Hjortspring boat: a centuries-old Viking-age relic that quietly reshaped our understanding of early Nordic seafaring. When this plank-built ship was unearthed in Scandinavia more than a hundred years ago, archaeologists began assembling fragments of its backstory. The vessel carried a treasure of weapons—swords, spears, shields, and more—that told of a confrontation aimed at the Danish island of Als, a clash that ended with the attackers defeated and their ship sunk in a bog. The bog preserved the wreck for over two millennia, awaiting modern methods to reveal its secrets.
New research released in PLOS One adds important pieces to the puzzle of where the invaders came from and when they set sail. The study combines radiocarbon dating with an analysis of the ship’s construction materials, suggesting the Hjortspring boat traveled farther than previously believed.
Lead author Mikael Fauvelle, associate professor of archaeology and ancient history at Lund University, explains that the findings offer a fresh clue about the raiders’ origins. He notes that, in the Bronze Age, Scandinavians needed to voyage by sea to obtain copper and tin for bronze, resources not mined locally at the time. Consequently, the Hjortspring boat stands as a culmination of one of Scandinavia’s early maritime cultures and provides insight not only into Iron Age seafaring but also into Bronze Age seafaring that preceded it.
A surprising discovery emerged from tar fragments on the boat: a partial human fingerprint, possibly left by one of the original crew. Fauvelle emphasizes that fingerprints from this era are rare, and this fragment could offer a direct link to a person who handled the vessel.
Before sinking, the Hjortspring boat stretched nearly 20 meters (about 66 feet) in length and could accommodate up to 24 rowers. Today it is exhibited at the National Museum of Denmark in Copenhagen. The craft comprises a bottom plank sewn to two side planks, with curved extensions at both ends, and it is regarded as the oldest well-preserved plank-built boat in Northern Europe. Coauthor Flemming Kaul, a senior researcher and curator at the National Museum of Denmark, highlights its significance as evidence of sophisticated early Iron Age shipbuilding in Scandinavia.
Shortly after the 1920s excavation, researchers pursued extensive studies to pinpoint the invaders’ origins. It wasn’t until 2024 that the team re-examined archived caulking—waterproof sealant—and the ship’s cordage, revealing crucial new information after more than a century. Previously, caulking was thought to derive from local materials like linseed oil or animal fat, but analysis showed a mixture of animal fat and pine pitch (pine sap) as the actual sealant.
The discovery of pine-based caulking raises the possibility that the Hjortspring boat was built in regions with abundant pine forests, possibly along Baltic Sea coasts rather than Denmark proper. If the raiders originated from that direction, it would imply a substantial, premeditated voyage rather than a spontaneous raid.
Fauvelle remarks that these insights illuminate a long-standing pattern: the Scandinavian seafaring tradition of raiding and trade has deep roots extending back to the Bronze and early Iron Ages, well before the Viking era. The findings also underscore that ancient Scandinavia was a highly interconnected region, with distant contacts and alliances influencing conflicts across broad areas.
Ole Kastholm, a veteran expert in ancient Scandinavian seafaring not involved in the study, finds the pine pitch discovery exciting. He agrees the Hjortspring boat may have originated from the Baltic region. Kastholm reminds us that early peoples navigated challenging seas in smaller, open vessels—whether logboats or plank-built craft like Hjortspring—demonstrating remarkable maritime capability long before the Viking Age. He also stresses the value of preserving museum collections; recent advances in analysis can extract new knowledge from artifacts once thought fully understood. His hope is to one day pinpoint the vessel’s exact geographical origin.
During the project, researchers recovered intact cordage from the archive, enabling radiocarbon dating for the first time in centuries. Although wood planks had been treated to preserve them for display, dating the ropes showed the vessel belonged to roughly the fourth or third century BC, aligning with earlier estimates.
The partial fingerprint remains an exceptional highlight, adding a human connection to the boat’s long history. Fauvelle notes that fingerprints from this era are exceptionally rare in tar, making this find particularly noteworthy.
Looking ahead, the authors aim to continue solving the Hjortspring mystery. They plan to analyze X-ray scans of the wood for tree-ring data and attempt to extract ancient DNA from the tar to help locate where the raiders came from. Kaul emphasizes that studies like this deepen our understanding of Early Iron Age conflict and strategy in Northern Europe and remind us that maritime history is inseparable from naval history. Controlling Baltic Sea routes and trade networks was as strategically vital then as it is today.
Taylor Nicioli, a freelance journalist based in New York, composes this report.
Would you like this rewrite to emphasize more speculative scenarios about the raiders’ origins, or would you prefer a tighter, more strictly evidence-driven version that foregrounds the radiocarbon and material analyses? All insights are welcome in the comments as we consider how ancient seafaring shaped regional power dynamics.
