A recent study published in the European Journal of Archaeology proposes a new interpretation for Scandinavia’s largest prehistoric earthen mound. The mid-sixth-century structure known as Raknehaugen appears to be a communal monument built to restore order after a catastrophic landslide. The research connects the massive earthwork in southeastern Norway to a period of sudden climate change and widespread environmental instability.
During the middle of the first millennium, the people of the Scandinavian Peninsula experienced a period of profound social and environmental change. The transition from the Early to the Late Iron Age saw shifts in agricultural practices and the emergence of massive earthen mounds across the local landscape. The people living in the Romerike district of present-day Norway inhabited an area situated at the boundary between two distinct environments. To the north lay sandy, nutrient-poor plains rich in timber, while to the south and west the terrain consisted of heavy marine clays that formed deep ravines and fertile soils.
Raknehaugen sits exactly on the border of these two landscapes. In its original form, the structure measured roughly 77 meters across and 15 meters high. The long-standing archaeological convention has framed the large mounds of this era as displays of emerging political power and centralized wealth, operating on the assumption that the amount of labor required to build a monument directly correlated to the prestige of a specific deceased individual. The outstanding mystery regarding Raknehaugen stems from the absence of internal burial chambers, primary human remains, or grave goods, leaving the structure’s true function unresolved despite 150 years of extensive archaeological excavations.
The paper was authored by Lars Gustavsen, an archaeologist at the Norwegian Institute for Cultural Heritage Research. Gustavsen reevaluated archival data from massive excavations conducted in 1869 and 1939, which mapped the mound’s highly unusual interior architecture. To understand the monument’s relationship to its environment, Gustavsen also utilized modern remote sensing technology called light detection and ranging, commonly known as LiDAR. This technique involves scanning the earth with lasers from an aircraft to create highly detailed topographical maps, revealing subtle features of the ancient landscape hidden beneath modern vegetation.
The archival data provided detailed records of the materials used to build the mound. The structure rests on alternating deposits of sand and clay, topped by three separate horizontal layers of timber. The uppermost timber layer alone consists of approximately 25,000 logs and branches. Previous studies of these tree rings, a method known as dendrochronology, showed that the trees were mostly felled in a single year. These tree rings also contained an abnormally narrow growth band formed exactly 15 years before the trees were felled, a biological signature that researchers have connected to a well-documented global climate downturn, though the study notes some uncertainty in this dating.
The LiDAR analysis revealed a massive, previously unassociated geological feature located immediately south and west of the mound. The terrain features a sharp drop that traces a continuous curved ridge nearly four kilometers long, enclosing an irregular depression covering about one square kilometer. This distinctive scar is the physical remnant of an enormous ancient landslide.
The predicted timing of the mound’s construction aligns closely with the geological disaster. In the year 536 AD, a series of volcanic eruptions blanketed the Northern Hemisphere in an atmospheric dust veil, dropping temperatures, reducing sunlight, and increasing precipitation. As the climate worsened, the local population shifted from growing crops to raising livestock. The combination of heavier rainfall, cooler temperatures reducing evaporation, and the removal of water-absorbing vegetation due to animal grazing would have saturated the local soils. These conditions destabilized the marine-deposited earth in the Romerike district, forming a liquid state known as quick clay that triggered the massive landslide.
The physical evidence within the mound suggests a direct response to this traumatic earth movement. The timber layers consist mostly of young, stubby pine trees alongside deciduous species like birch and alder, sourced from an area of roughly one square kilometer to the south of the mound. Many of the logs were broken rather than chopped, while others were cut unusually high on the trunk or included intact root systems, indicating the trees were uprooted or buried by earth rather than deliberately felled by woodsmen.
The location and materials suggest the local community gathered timber directly from the landslide debris field and used it to construct a protective barrier or offering on the very edge of the geological scar. The structure rests precisely on the fault line between the safe, stable forest lands and the volatile, collapsed ravines. The enormous collective labor required to move thousands of cubic meters of soil and tens of thousands of logs served as a communal ritual intended to process a trauma, appease natural forces, and reestablish cosmological order in an era defined by hunger and instability.
The primary challenge in verifying this sequence of events is the lack of direct dates for the landslide itself. The connection between the climate disaster, the landslide, and the mound construction relies on spatial proximity and the condition of the timber, leaving open the possibility that the landslide occurred at a different time. The visual alignment of the geological scar offers a strong circumstantial case, yet it requires physical confirmation through targeted sampling.
Future research will focus on geological field testing to close this chronological gap. Investigators plan to conduct detailed soil analyses of the landslide zone to determine the specific type and volume of the collapse. Archaeologists and geologists could also apply luminescence dating to the exposed sediments on the landslide scar. This dating method calculates the last time mineral grains were exposed to sunlight and would establish a definitive link between the collapse of the terrain and the construction of the monument above it.
The paper, “The Late Iron Age Mound Raknehaugen in Norway: A Ritual Response to the Sixth-Century Crisis,” was authored by Lars Gustavsen.
(Photograph: unknown, 1906, Museum of Cultural History, Oslo. Reproduced under licence CC BY-SA 4.0.)