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| Image credit: Øyvind Nesvåg / Rogaland County Municipality |
The Discovery
Archaeologists opened the Grønhaug burial mound on Karmøy last week, part of an ongoing effort to investigate a site that had, in the words of archaeologist Marie Ødegaard of the University of Stavanger's Museum of Archaeology, "been somewhat forgotten." Ødegaard is leading the excavation together with fellow archaeologist Håkon Reiersen from the same institution.
Grønhaug sits among a row of several large burial mounds on Karmøy dating from a wide range of periods, some reaching back as far as the Bronze Age. Inside the mound lie the remains of a Viking ship, believed to have been around 15 metres long, first investigated by archaeologist Haakon Schetelig in 1902, who confirmed that a ship had indeed been buried there.
What Archaeologists Found
Parts of the ship's bottom and hull are probably still preserved inside the mound. During Schetelig's original 1902 excavation, archaeologists removed loose pieces of the ship's planking from around the oar holes, which were particularly well preserved at the time, and transported them to Bergen for study. According to Ødegaard, most of the remaining material was likely left in place because the wood itself was too soft to safely remove. The mound has not been reopened since that original excavation, according to the Norwegian Directorate for Cultural Heritage, which commissioned the current work in collaboration with Rogaland County Municipality.
The current excavation, part of a broader effort to recommend additional Viking sites for inclusion on the UNESCO World Heritage List, has opened a trench into the mound roughly corresponding to the one Schetelig excavated in 1902, with a small extension. This remains a limited excavation, meaning the entire mound is not being opened. Archaeologists have so far found one or two rivets, probably originating from the ship itself, alongside pieces of timber that Schetelig discarded during his original excavation. This timber appears to be pine rather than oak, the wood typically used to build Viking ships, suggesting it may instead have formed part of a roof or other structure aboard the vessel, such as a superstructure.
Historical Background
The ship itself is very badly deteriorated, meaning relatively little of the vessel survives intact. However, preliminary investigations indicate that preservation conditions inside the mound are otherwise very good. The grave has also been looted at some point in its history, a circumstance common to ship burials of this kind and one also documented at the famous Oseberg ship burial elsewhere in Norway.
Archaeologists have taken the opportunity to closely examine a layer of birch bark discovered inside the mound. Ødegaard explained that this bark was previously thought to be connected to looting activity at the end of the tenth century, potentially laid down either so people could walk through the mound without getting their feet wet, or for some ritual purpose, perhaps intended to avoid disturbing the spirits believed by some to dwell within such burial mounds. However, Ødegaard noted that researchers are now becoming less certain about this interpretation, and the birch bark may instead have formed part of the mound's original construction.
Scientific Analysis
One of the central unresolved questions concerns what lies beneath Grønhaug itself. Several other burial mounds in the surrounding area date back much further than the Viking Age, to the Bronze Age, and the archaeologists have now found clear evidence of a similar earlier structure at Grønhaug. Excavating down to the old ground surface exposed when the Viking ship burial was originally constructed, Ødegaard described being able to see blueberry plants and heather still growing there at the moment of construction, with the plants even retaining their leaves, indicating the mound was built over this vegetation during the summer half of the year.
The archaeologists have now excavated through the Viking-era mound and confirmed the presence of a man-made stone cairn beneath it, covered by several layers of soil and turf, with stones also arranged around the base of the older structure forming what is known archaeologically as a kerb. This older Bronze Age mound appears to have functioned as a kind of platform upon which the later Viking grave was constructed. This discovery has only just been made, meaning further sampling will be required to establish a more reliable timeline for the earlier structure.
Why This Discovery Matters
The dating of the Grønhaug ship itself has long been the subject of scholarly debate. Earlier studies suggested the ship may have dated from around the year 780, with burial taking place a little over a decade later, placing the grave just before the conventional start of the Viking Age. However, newer dating work combining dendrochronological and radiocarbon methods indicates the ship instead dates from around 864, with the burial mound itself possibly constructed a few years earlier still, placing it firmly within the Viking Age proper, comparable in period to the Oseberg ship, which dates from the year 820.
This ongoing refinement of Grønhaug's chronology, combined with the newly confirmed Bronze Age structure beneath it, offers a valuable opportunity to understand how this particular stretch of Karmøy's landscape was used and reused across an extraordinarily long span of prehistoric and early historic time, with successive generations apparently choosing to build new monuments directly atop far older ones.
What's Next?
Ødegaard noted that dating of the ship and mound has become considerably more precise in recent years, though some discussion remains, and the team hopes the current investigation will allow even more precise dating to be established going forward. Part of the further analysis planned will involve dating the underlying Bronze Age mound more precisely, building on the preliminary findings made so far.
As part of the broader effort to support the nomination of additional Viking sites for UNESCO World Heritage status, continued study of Grønhaug's exceptional preservation conditions, its ship remains, and its newly revealed Bronze Age foundations is expected to contribute significantly to the wider case being built for the site's historical importance.
Conclusion
The reopening of the Grønhaug ship burial after more than a century has revealed a site far more layered and complex than its Viking Age reputation alone might suggest, with remarkably preserved Viking-era vegetation sitting directly above the stone remains of a far older Bronze Age monument. As archaeologists continue to refine the site's chronology and investigate the relationship between its two burial phases, Grønhaug stands as a compelling reminder that even a single burial mound can hold thousands of years of layered human history, waiting patiently to be uncovered.
FAQ
Q: What has been discovered at Grønhaug? A: Archaeologists reopening the Viking ship burial mound have found rivets and timber from the ship, alongside a previously unknown Bronze Age stone cairn buried beneath the Viking grave.
Q: When was Grønhaug last excavated? A: The mound was first investigated by archaeologist Haakon Schetelig in 1902 and had not been reopened until the current excavation.
Q: How old is the Viking ship burial? A: Newer dendrochronological and radiocarbon dating indicates the ship dates from around 864 AD, with the mound itself possibly constructed a few years earlier.
Q: What did archaeologists find beneath the Viking grave? A: They uncovered a man-made Bronze Age stone cairn with a surrounding stone kerb, which appears to have served as a platform for the later Viking ship burial.
Q: Why is preservation at the site considered so remarkable? A: Archaeologists found Viking Age blueberry plants and heather with intact leaves preserved beneath the mound, along with well-preserved birch bark and wood fragments.
