Rediscovering a forgotten power centre

Archaeological investigations at a site in the Norwegian countryside have uncovered evidence of a rich history stretching back thousands of years. Amy Brunskill spoke to Jes Martens and Christian Løchsen Rødsrud, who led the research, to find out more.

Today, the site of Sem, located in Øvre Eiker, about an hour’s drive from Oslo, lies beneath unassuming agricultural fields. But historical sources reveal that the area was once home to several important institutions, including a thing (assembly), an early church, and a medieval manor house that went on to become part of the largest estate in Norway in the Renaissance, before being acquired by the crown in the 17th century and transformed into a seat of regional administration or ‘Lensherresete’, which was even visited several times by King Christian IV (r. 1588-1648). By the 18th century, however, the site had declined in importance, and eventually it was forgotten.

In 2014, metal detectorists exploring the area began to uncover a variety of surprising artefacts, including a Late Bronze Age pin, a fragment of an Irish reliquary, pieces of Viking Age hacksilver, and part of a Frankish belt. All of this material suggested that the site was of greater archaeological significance than anyone knew. Over the years that followed, further metal-detecting searches and ground penetrating radar (GPR) surveys were carried out, revealing other intriguing hints as to the site’s history. Most of this investigation was focused on the field to the west of the road running through the site, but this summer archaeologists from the Museum of Cultural History, University of Oslo, got their first chance to excavate at Sem in the eastern field, in advance of a drainage project.

This summer’s excavations in the area have produced further evidence that Sem was once an important power centre. In the past, the level of the river (seen on the far right) would have been much higher and large ships could have sailed all the way up from the sea. Image: Frank Røberg, Viken County council, Museum of Cultural History 

An array of artefacts

Before excavations could begin, a GPR survey of this field was carried out and a metal-detecting search conducted. The search produced many of the same sorts of objects as the area across the road, all supporting the idea that Sem was an important settlement and trading centre during the Viking Age and Iron Age, with activity stretching back as far as the Late Bronze Age.

By the time the excavations began, metal detectorists had recovered a total of over 500 objects from the ploughsoil in the fields at Sem. Among the most impressive was a fragment of an ornately decorated sword hilt (a second piece was recovered nearby during excavations). The sword dates to the 7th/8th century and is of a type also found in eastern Scandinavian boat burials and at Sutton Hoo, indicating that activities associated with the same high level of society were taking place at Sem. Also discovered were 64 brooches – spanning the pre-Roman Iron Age to the medieval period – some in mint condition, suggesting that they were being produced at the site. The detectorists found several gold objects, too, including small metal droplets indicative of goldsmithing. Other finds, including buckles and fixtures from across northern Europe, coins from the Middle East, and a large quantity of weights make it clear that Sem was once a bustling centre of commerce with connections stretching across Europe and beyond. In fact, ‘Sem’ is a corruption of the site’s earlier name ‘Sjøheim’, meaning ‘landing place’. Today, it is located firmly inland, but in the past water levels were higher and the river that runs alongside the settlement would have been a fjord that allowed large boats to sail from the sea all the way up to Sem.

This fragment of an ornate sword hilt (above) indicates that high-status individuals were present at Sem. A modern reconstruction, made by sword smith Nils Anderssen, shows how it may have looked (below). Images: Museum of Cultural History; Nils Anderssen,

Below the surface

Metal-detecting and GPR surveys both played a critical role in identifying the site’s significance, but the excavations this summer offered a valuable opportunity to see what archaeology lay below the soil. The most exciting discovery came as a surprise to archaeologists: a huge longhouse, which had not shown up on the GPR survey. Two rows of large postholes reveal that the house was an impressive 9m wide, and perhaps four to six times this in length, although the structure continues under the road and likely into the field beyond, so has not been excavated fully. A secondary row of postholes was identified 3.5m outside the roof-bearing wall posts; perhaps these held slanted posts to strengthen those supporting the roof, or formed passageways, or even pens for animals, on the outside of the building instead – we can only hypothesise at this stage. Also currently a subject of debate is the house’s date; the closest known parallels for this type of building are from the Viking Age, but it is hoped that samples from the postholes will contain material that can be radiocarbon dated to provide a firm chronology.

At the northern end of the field, excavations uncovered a set of Iron Age cooking pits. These features are believed to have been associated with feasting and celebrations, due to the vast quantity of animal bones and pottery they contain, including pieces of ornate vessels likely connected to the drinking that occurred during a special occasion. Also discovered in the pits were three beads; it is not clear how they ended up there, but this unusual find offers further evidence of the richness of the site. Several other structures were identified during excavation as well, which could not be excavated in their entirety but produced samples that the archaeologists hope can be radiocarbon dated.

Above & below: The archaeologists uncovered a set of postholes (in blue on the plan, marked with white posts in the photo) belonging to a large longhouse, 9m wide and believed to stretch under the road and into the field beyond. Images: Museum of Cultural History  

Unfortunately, one part of the site’s history that could not be explored in detail was the medieval and Renaissance phase, as the Norwegian Cultural Heritage Act – with a few exceptions – does not protect archaeology dating to after 1537. Incidental finds from this period, which include animal bones and oyster shells as well as the ornamental handle of a knife or fork, offer a glimpse of a noble household living here in style. Sadly, however, Norwegian museums are not permitted to take these artefacts into their collections, and any archaeology from the post-1537 occupation of the site that remains in the field must now be left to the plough.

Post-excavation work is currently underway, and it is hoped that future archaeological work in the surrounding area may be possible, to help researchers piece together a more comprehensive understanding of Sem through time. For now, though, the discoveries paint an intriguing picture of a place where people from all parts of society gathered, traded, worked, and lived, for centuries longer than previously thought.