The Follo Line Project

Exploring medieval Oslo

Since 2013, the largest infrastructure project in modern Norwegian history has granted a team of more than 40 archaeologists an extraordinary glimpse of medieval Oslo. One of the biggest questions they aimed to answer is what the medieval town really looked like. Thomas Wrigglesworth shares some of their discoveries.

The archaeological investigations recently undertaken in the middle of Oslo’s medieval town took place on a vast scale. One of the first things that visitors noticed was the interplay between the archaeologists and the massive construction operation. From a distance, the excavations evoked an anthill teeming with activity, calling to mind childhood memories of Richard Scarry picture books. Working under such circumstances meant the team had to respond both to archaeological issues and to the project construction schedule. This required effective project leadership and frequent contact between archaeologists, authorities, and contractors. And all of this while impressive remains of medieval building foundations, fortifications, and roadways were turning up.

‘It’s pretty remarkable that we had so much archaeology conserved here, when concrete culverts were being assembled by cranes just a few metres away,’ says Egil Lindhart Bauer, Head of Oslo Division at the Norwegian Institute for Cultural Heritage Research (NIKU) and former Project Manager for the Follo Line excavation. But why is Oslo so rich in medieval archaeology? A headstrong Danish king of the 1600s holds the answer.

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Medieval Oslo

According to the Norse sagas, Oslo was founded by the Norwegian king Harald Hardrada in AD 1049, beside what is now the aptly named Oslofjord. Archaeology, though, tells a different story, as the discovery of Christian burials dating back to before AD 1000 suggests earlier settlement in the area. Questions about the precise foundation date are far from being the only uncertainty surrounding Oslo. Today, there is no shortage of reconstruction drawings of the medieval town, which can make it easy to assume that we have a clear sense of what it looked like.

In reality, relatively little is known about the settlement. This state of affairs can be traced back to the 17th century, when Oslo’s inhabitants were forced to vacate their town. This eviction occurred before anyone had drawn maps or panoramas – with the exception of an inaccurate rendering on the 16th-century sarcophagus of King Frederik II – or even set down detailed descriptions of the town. Oslo’s appearances in the Norse sagas, for instance, were geared towards an audience already familiar with it, and so did not need much orientating. Centuries later, it is not so easy for modern readers to get their bearings. Some surviving deeds and property documents do offer glimpses of parts of the town, but this is a partial picture at best. So modern archaeologists cannot draw on rich written sources to guide their excavations.

And this is where that headstrong Danish king enters our story. It was Christian IV who ordered the abandonment of the medieval town after a fire in 1624. He decided to relocate its inhabitants to the other side of the fjord, below an imposing castle known as Akershus Fortress. This move was motivated by ambitious plans for national security. ‘He wanted to build a new city: Christiania,’ says archaeologist Håvard Hegdal, who has lengthy experience with excavations for the Follo Line Project. ‘This could then be equipped with bastions, bringing it up to date with contemporary defensive technology. Having long, straight streets was also important, as they created avenues that cannons could fire down to repel any invading Swedes.’

But visions of Oslo rising phoenix-like from the ashes as a state-of-the-art fortress city never came to pass. Instead, while the Swedes were installing an ambitious fortification of their own at Gothenburg, the defences of Christiania remained modest. Despite this failure to realise the grandiose vision for Christiania, the new settlement ultimately developed into modern Oslo. ‘The area of the old town – that is to say, the medieval town – lay outside Christiania’, says Håvard. ‘Archaeologically, this proved very, very valuable, because inside a city centre you will naturally bury pipes, build cellars, and construct all kinds of things that damage buried archaeology. As modern Oslo lies on a different site, when current work on the railway started, many generations of medieval town foundations still lay more-or-less intact beneath the fields outside the city.’ Indeed, this is not the first time that railway work has occasioned a closer look at the archaeology of Old Oslo.

Archaeology starts and ends with the railway

In many ways, the history of archaeology in Norway both starts and ends with that of the railway. Archaeology as a discipline first became established in the country thanks to discoveries made while track was being laid in the second half of the 1800s. As far as Oslo is concerned, the ruins of churches and the palaces of bishops and kings still remained partly visible in the old town, meaning knowledge of its presence was never truly lost. But discovering traces of more humble wooden houses during railway work, particularly the 1870s development of the Smålens Line, ignited an interest that has endured ever since. With hindsight, we can see the railway also brought another benefit. Because it came to dominate this part of modern Oslo – with the ruins of a church known as the Mariakirken lying only a few centimetres from the tracks – the area was not seen as a prime patch for building developments, helping to preserve the archaeology.

Egil feels the recent archaeological investigations in Oslo have two major advantages. ‘On the one hand, we have the deep dives into medieval Oslo that the Follo Line Project has allowed, including vast areas that are new to archaeological investigation, such as under Bispegata [Bishop’s Street]. This included one large pocket of archaeology that, apart from some railway diggings over 60 years ago, had not been disturbed since the Middle Ages – with excellent conditions for preservation and discoveries of both stone and wooden buildings. Very exciting. On the other hand, it is the sheer size of the project, geographically speaking, in addition to all of the smaller projects around the city and the opportunities we now have to bridge the gap between areas that were examined at earlier times.’

Sometimes the overlap between early and modern work has proved all but seamless. ‘There was part of a wooden log that was partially excavated in the 1800s,’ says Egil, ‘and we found the remainder in 2018. That is a special feeling.’ On another occasion, a plan of part of a stone building excavated in the 1950s slotted on to the remainder of the structure found during current work. Bringing these results together is allowing the archaeologists to reconstruct an ever more fine-grained map of the medieval town. At the same time, of course, joining the dots is not always straightforward, as 19th-, 20th-, and now 21st-century excavators adopted different approaches to recording what was found.

‘So much material was excavated in the western part of the city during the 1800s,’ says Egil, ‘but we don’t have much detailed information about it. There are sketches showing the remains of houses, but very little is known about stratigraphy or different phases.’ By contrast, work in the 1970s and ’80s was recorded to a high standard. Now the Follo Line Project is raising the bar higher still, while focusing on digital documentation, and collecting a much wider range of material for study.

Such care is paying dividends when it comes to building up a more sophisticated picture of the town. ‘Now we can see that what we thought we knew about the town from the 1970s and ’80s investigations – when it was more common to extrapolate from the structures that were found to reconstruct the rest of the settlement – may have been incorrect,’ says Egil. To put it another way, medieval Oslo no longer looks the way we thought it did just a few years ago.

From wooden town to divided city?

Although post-excavation work on the Follo Line findings is still under way, it is already clear that archaeologists must reckon with a more varied settlement than previously suspected. One illustration of this concerns how views of the development and function of stone buildings have shifted. While it has always been appreciated that masonry was used for Old Oslo’s major landmarks, like the royal palace, bishop’s palace, and the main churches, such structures were previously identified as high-status exceptions to the general picture of a wooden town.

‘Excavations in recent years have shown that stone buildings were more common than the surviving written sources imply,’ says Egil. ‘Combining them produces references to 16 stone buildings, but in the 2013-2018 excavations alone we encountered four buildings within a small area.’ This is not the first time such residences have been encountered, although in the past they have been routinely dated to the 16th century or later. Such a chronology was justified on the assumption that masonry construction became more frequent after stone was available to recycle from churches torn down during the Reformation. The current work, though, shows that several stone buildings date to the turn of the 13th and 14th centuries. So who lived in these houses? Given that some examples cluster together, they might signify a powerful social group. Could they be merchants, or perhaps people linked in some way to the king, the bishop, or the town’s administration?

Thinking along these lines raises the possibility that medieval Oslo had several distinct quarters. If so, it helps explain activity within the settlement. Buildings on a crest of higher ground, for instance, proved to be in continual use, and displayed numerous building phases, some presumably explained by repeated evidence for fire damage. ‘The area is elevated and has natural drainage,’ says Egil. ‘To me, this suggests an attractive location. It’s dry, and close to the main streets that acted as arteries through the town, with the palace of the bishop at one end and that of the king at the other. In short, the signs point to it having been a desirable place to build and live.’

Activity on an adjacent plot of ground, which slopes westwards towards the fjord, provides an intriguing contrast. Archaeologists identified terracing that had previously passed unnoticed there, while the associated buildings displayed fewer construction phases than their neighbours on the higher ground. ‘At first glance, this could be a result of it being a less attractive area,’ Egil says, ‘but rather it may be a product of the stone buildings that we found there. The greater lifespan of masonry structures would have created less need for elements to be replaced and rebuilt. What’s more, because these buildings were less vulnerable to the fires that periodically ravaged the adjoining quarter, they may have helped limit the spread of such burning.’

Moving further west towards the waterfront sees the nature of activity shift once more. There is less sign of housing, with some space given over to pens used for animal husbandry. Beyond them, though, buildings clustered densely once again. This time the attraction was presumably the harbour, rather than the suitability of the ground, which appears to have been naturally damp and swampy. A graphic illustration of this came from the excavations south of Bispegata during 2015-2016, which produced abandoned buildings that had pretty much rotted to the core.

Finds indicate this waterfront offshoot of the town was abandoned while the harbour was still active and before Old Oslo was abandoned wholesale. Loss of this portion of the settlement might be due to depopulation following the 14th-century bubonic plague, although other factors could certainly have played a part. Whatever the trigger, it left the main town crowded on the crest of higher ground, with a gap between it and the harbour. This layout probably helped to save the port facilities in 1352, when a fire reportedly razed the entire town apart from the storage houses in the harbour, suggesting the open ground acted as a firebreak.

How big was the Bishop’s Palace?

One of the most important areas examined during the Follo Line Project was around the Bishop’s Palace. Although the heart of this complex had previously been excavated, revisiting the site allowed archaeologists to confirm a hypothesis from the mid-1900s: the palace sat within a larger compound boasting a vast ring wall that ran towards the water. ‘There was little trace of any ordinary settlement here,’ says Egil, ‘but we did find a large stone building with a wooden floor that clearly served as a special public building. Within it we discovered ample evidence for the festivities that were once held there.’ This merrymaking generated a wealth of finds, including large quantities of animal bones – especially chickens – fine beads, several gaming pieces, and a flute.

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‘The archaeological results from the Follo Line Project show an expansion of the Bishop’s Palace during the early 14th century,’ notes Egil, ‘which is interesting in itself.’ There has been some speculation that activity in the town was sparked by the death of Haakon V Magnusson in 1319, which led to the royal seat of power being relocated from Norway and Oslo to Sweden. ‘Perhaps more distant royal oversight presented an opportunity for the bishop or other prominent figures to expand a bit more, resulting in more stone buildings being constructed,’ he says.

Main Street, Oslo?

A discovery that attracted plenty of Norwegian media attention was a stretch of one of medieval Oslo’s main streets, Bispeallmenningen. This interest can be explained by a longstanding discussion surrounding the precise course it took. Archaeologists have maintained that the thoroughfare followed a similar route to the current Bispegata (Bishop’s Street) and led from Bispeborgen (the Bishop’s Castle) on the crest of high ground down to the harbour. Work in 1953 by Cato Enger produced evidence to support this hypothesis, and the current investigations have confirmed the presence of a lengthy street stretching towards the wharves, where the archaeologists are still digging.

‘In practical terms, we have found the entire Bispeallmenning,’ says Michael Derrick, who is overseeing excavations ahead of the laying of tram tracks on the site. ‘Even in those areas where we haven’t excavated, we now have a pretty clear idea of its location.’ The archaeologists also have a good grasp of the general state of the Bispeallmenning when it was in use, which came as quite a surprise. ‘We were visualising a thoroughfare with neat plank coverings, an even width, and tidy resurfacing as and when required’, Michael says. ‘Instead, we found a pretty shabby street.’

How could it be that an essential public route, which was open to all and allowed access to the harbour, was permitted to deteriorate in this fashion? The archaeologists suspect that maintenance was divided between certain citizens, likely those owning property along the road, who proved less than diligent in discharging their responsibilities. Indeed, some properties were even extended so that they encroached on the street. But while running repairs to the road may have left much to be desired, the manner in which it was engineered is of considerable interest. To counter sloping ground, logs were laid to form a bed that evened out the street level. These beds were edged with further logs to form a sort of shallow box, which contained loose fill. ‘People were apparently walking on these deposits – wood chippings, filings, or earth – rather than the wooden structure itself,’ says Michael. ‘One indication of this is that the log beds do not have an even base suitable for walking on, let alone driving a wagon or cart over, so it is likely that large parts of Bispeallmenningen were covered in loose deposits while being used.’

The case of the Bispeallmenning is also notable for the impact that media attention had. While it was the physical parts of the street that first captured public interest, questions then began to be asked about what would become of these remains. Archaeologists working on development projects are generally used to structures or features being dug up and – after meticulous documentation to create a permanent record of what was found – then discarded. For the wider public and history buffs, though, this proved a bitter pill to swallow. After intense debate, the Department of Cultural Heritage and the Museum of Cultural History ended up removing and preserving nine logs from the street corduroy.

Although archaeological work over the decades has revealed a general sense of medieval Oslo’s layout, recent work has presented a much stronger sense of what it would have been like to walk these streets. ‘At Bispeallmenningen, we can imagine the Bishop’s Palace on one side of the street, enclosed by a tall ring wall,’ says Egil, ‘while on the other side there were huge storage buildings with foundations that indicate massive quantities of goods were held there. Then we have the stone houses, which must have been owned by prominent people who could get away with allowing them to encroach on the street. If we could be there during the 1300s, the passage would seem quite narrow, as well as darker and more claustrophobic than we might be comfortable with today.’

Another fresh insight comes from traces of a possible moat. ‘We have found indications that the royal palace of Oslo, which occupied a terrible position from the point of view of military defence, may have been separated from the rest of the settlement by a moat,’ says Egil. ‘This strengthens the idea that there was clear zoning within the town. You can imagine: the king’s area – within a moat; the bishop’s area – behind a massive ring wall; the high-status citizens in their area on the slope crest; animal enclosures down towards the harbour; and then, in the boggy area by the port, some shabby, lower-status buildings that were possibly abandoned during the Black Death and rotted away. At the furthest western point, we have the harbour, with storage houses and wharves, which were gradually built further and further out into the harbour basin, as the land rose.’

Following up – what now?

Although smaller excavations are still under way, the larger ones are finished – for now. As a result, the post-excavation phase is getting into full steam, allowing the archaeologists to deploy techniques that were not available to earlier investigators. ‘Dendrochronology has improved,’ says Egil, ‘and radiocarbon dating costs less, so we can create a more fine-meshed chronology for the buildings. Another important tool is DNA analysis. For the first time, this has allowed us to detect bubonic plague in skeletal material. So, while the skeletons of people who died from the plague have very probably been discovered in the past, now we can prove it.’ Over the course of the work, more than 100 skeletons were excavated in situ, while additional bones belonging to a minimum of about 500 individuals were recovered. Further research on these promises to complement our increasingly detailed view of medieval Oslo itself, with a greater understanding of the reality of life within the town. Many strands of evidence will help to build up this picture, including the detailed archaeobotanical work undertaken during the excavations.

As well as providing an opportunity to take a detailed look at what was found, this stage presents a chance to reflect on what the wider Oslo public found most interesting about the dig. ‘We’ve found that what we think is impressive doesn’t always match what the wider population considers “cool”,’ Egil notes. ‘But we’ve discovered many well-preserved items. The best ones can be seen at our Instamuseum (www.instagram.com/niku_archaeology). Many of them come from what we have been referring to in jest as “the Bishop’s garbage pile” – as its name suggests, a large rubbish midden that happened to lie near the Bishop’s Palace. Whether or not the bishop was actually generating this rubbish is unclear, but the finds clearly need to be seen in the context of a high-status environment.’ Among the highlights from the rubbish are a fragment of tablet-woven silk band with inlaid gold brocade, a pewter miniature knight, and a cabochon cut-rock crystal, which could once have adorned a ring, a book cover, or even a reliquary.

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Some other finds that excited wider interest are more macabre in nature, such as a skeleton buried with rocks in its mouth (a practice rooted in superstition and supposed to avert danger from the living dead), infants discreetly interred on the outskirts of cemeteries, and the eye-opening number of young men’s skulls that bear traces of fatal injuries. Taken together, the evidence for actions ranging from elite waste disposal to violent death begins to create powerful snapshots of what it was like to live and die in this town. Pulling all of these discoveries together has transformed how we regard Oslo in the Middle Ages, prompting NIKU to assemble some 30 researchers to collaborate on a new standard work about medieval Oslo. Work on the book is currently under way and it is due to be published in 2022, coinciding with the opening of the Follo Line.

Another offshoot from the project that the archaeologists welcome is the creation of a heritage attraction over the course of the new railway lines. Rather than leaving the track open to the sky, the Follo Line can claim a world first, by covering over part of the railway to create a medieval park, where reconstructions and information panels, as well as a range of online resources (some available in VR and AR), will present what has been learned about Old Oslo. The medieval town is hopefully facing a bright future.

Further information
Digital 3D models from the Follo Line Project can be examined here: https://sketchfab.com/nikunorway/collections/follobanen.
For more on the Follo Line Project, visit their website at: www.niku.no/en/prosjekter/follobaneprosjektet.

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This is an extract of an article featured in issue 106 of Current World Archaeology. Click here for more information about subscribing to the magazine.