Second Week Of 2016 Excavations At Skällvik Castle

Our second week at Skällvik Castle proved a continued small-finds bonanza, and we also documented some pretty interesting stratigraphy.

  • More of everything in Building IV. In addition to more coins of Magnus Eriksson, dice and stoneware drinking vessels, we also found a lot of points for crossbow bolts. It’s starting to look like the castle guards’ day room! As for why we found crossbow bolts only inside one building and none outdoors in the bailey, I figure that they had been amassed there for re-fletching. The dark indoors find context and the undamaged sharp points show that the bolts did not end up in the floor layer of Building IV because people were shooting there.
  • Building IX has a lovely floor sequence. First a terracing layer with few finds, probably pre-dating the entire building. Then a culture layer. Then a stone cobble floor. Then clay full of magical fairy stones. Then mortar. Then large square unglazed brick tiles, only a few of which survived. Then a demolition layer mixed with household refuse. Such attention paid over time to the floor of a low-ceilinged cellar-like ground-floor room demonstrates the resources available to the castle’s owner.
  • Building X has had a nice ribbed brick portal, as evidenced by broken decorative bricks left by the quarrymen.
  • The gate house is still very rich in bones, as remarked on by the 1902 excavator. And his coffee-loving workmen or their contemporaries left a small midden in it after the end of fieldwork.
  • Two finds in particular document the presence of the social elite, which is hardly surprising at a royal castle where both King Magnus and the Bishop of Linköping dated letters. One is part of a wheel-turned ivory ear scoop, the Q-Tip of the era’s nobility from the NW building. The other is a seal matrix with a simple coat of arms, found near the castle dock. I’m optimistic that specialists will be able to read the inscription and identify the owner.
  • We have enough coins to be able to draw chronological conclusions not only from which types are there, but from which ones are missing. All but one of the coins we have identified so far were struck for Magnus Eriksson, most during his final minting period about 1360. His successor and nephew Albrecht was crowned King of Sweden in February of 1364, and this ruler is represented by only one coin, a frontal crowned-face bracteate.
  • We can see the quarrying of the castle for building material, targeted largely towards bricks, preferentially towards specialised decorative ones and floor bricks. These were in all likelihood taken by boat the two kilometres to Stegeborg Castle when it was re-erected, probably in the 1360s. And when Stegeborg was partly torn down about 1700, the bricks travelled on to the royal castle in my home town Stockholm!
  • It would be great to learn what’s under the rubble that fills the castle keep. But excavating this building would be an enormous undertaking, with regard both to the sheer volume of rubble with large heavy boulders, and to the long-term conservation commitment once you’ve emptied the structure. It is not a job for one precariously employed university lecturer and his students, working for a few weeks on small grants. The organisation that excavates Skällvik Castle’s keep will have to have solid long-term funding. And it must be willing to put a roof on the structure, restore the masonry and return the keep to daily use as a museum space with offices. Any responsible intervention into a ruin must be done with an eye to the far future, not just to the next tourist season.

First Week Of 2016 Excavations At Skällvik Castle

The famous royal castle of Stegeborg sits on its island like a cork in the bottleneck of the Slätbaken inlet (see map here). This waterway leads straight to Söderköping, a major Medieval town, and to the mouth of River Storån which would allow an invader to penetrate far into Östergötland Province’s plains belt. The area’s first big piece of public construction was 9th century fortifications intended to guard this entrypoint, in the shape of the Götavirke earthen rampart some ways inland and a wooden barrage at Stegeborg. This barrage was kept up for centuries, and indeed, the castle’s name means “Barrage Stronghold”.

Stegeborg is easily accessible by car and receives many visitors. Few of them however then continue on to the nearest castle ruin, which is oddly enough only 2 km to the SSW: Skällvik Castle. It sits on a rock outcrop on the south shore of the inlet, inside Stegeborg’s line of strategic defence and within sight of it. Why two castles so closely apart?

The written sources are rather murky, partly because they rarely differentiate between a manorial land property and a castle sitting on that property. But following my friend Christian Lovén’s treatment of the evidence, the timeline seems to be roughly this.

  • C. 1300. King Birger has Stegeborg Castle built.
  • 1318. Stegeborg is besieged and largely torn down in a civil war after King Birger has his rival brothers Erik and Valdemar starved to death in a Nyköping dungeon. Reports the Chronicle of Duke Erik from the victorious party’s perspective, “They broke down that wall so completely / They did not leave one stone on top of another”. King Birger is deposed and exiled.
  • C. 1330. King Magnus (the son of the murdered Duke Erik) or the regents during his minority refortify the Slätbaken passage, but with a new castle on the hill at Skällvik rather than on Stegeborg Island. About the same time, Skällvik Parish church is built between the two castle sites.
  • 1356. Skällvik is attacked by the forces of Erik Magnusson, rebellious royal pretender and son of King Magnus.
  • 1360s. Realising the obvious, King Albrecht (nephew of King Magnus) returns to the superior strategic position and rebuilds Stegeborg, quarrying the ruins of Skällvik for building material.

So Stegeborg and Skällvik Castles aren’t really two separate castles when seen on a strategic scale. They’re two versions of the same castle that has moved slightly to and fro over its 400-year lifetime, leaving a fossilised mid-14th century version at Skällvik.

Unlike Stegeborg Castle, which was maintained and extended up to the 1690s, nothing was ever built on Skällvik Castle’s foundations. Only recently was a small-scale brickworks established at the foot of the castle hill. In 1902 restoration architect A.W. Lundberg considerately removed a lot of the rubble from the ruins, leaving the culture layers easily available to the excavator everywhere except inside the keep. In the past week, me and my team have been the first archaeologists to take advantage of this state of affairs.

In addition to the high keep, Skällvik Castle has three main buildings arranged around its sloping bailey. They are joined up by short stretches of perimeter wall. We have opened trenches inside all three buildings (two in the long building IX-X) and in the bailey along the wall of building X. In addition we have test-screened and metal detected two big spoil dumps from 1902, and skilled metal detectorists have investigated our trenches and the surface around the foot of the castle hill. A few of our main results so far:

  • Five of six Medieval coins date from about 1360. The sixth is too corroded (i.e. debased) to allow dating before conserved. Two were minted in nearby Söderköping, one in Kalmar.
  • All other coins date from 1800 or later.
  • Building IV, where Lundberg identified a baking oven in 1902, has yielded all five datable Medieval coins, a bone gaming die and a piece of fine burgundy stoneware, probably from Lower Saxony. Drinking and gambling in the warmth of the bakery!
  • Building IX has yielded a fine cobbled cellar floor and a comb fragment.
  • The two 1902 spoil dumps are erosion rubble and brick kiln refuse, respectively, and not productive of small finds.
  • Unlike Birgittas udde, Skällvik Castle offers many preserved bones.
  • I have demonstrated experimentally (and idiotically) that when clearing brambles, you should wear protective glasses. I was lucky to only get my left cornea nicked a little. Hurt pretty bad and left me barely functional for two days.
  • Stoner dudes parked by the authorities at your religious abstainer hostel provide much entertainment with their spaced-out antics and conversation. Unless you mind food, cigarettes and bikinis going missing. And nocturnal rearrangement of furniture. And heavy bass at two in the morning.

Second Week Of 2016 Excavations At Birgittas Udde

We spent Thursday afternoon backfilling. As I write this, only trench G remains open, and the guys there expect to finish soon. Here’s some highlights of what we’ve learned during our second week at Birgittas udde.

Trench A in the outer moat demonstrated that the moat had a wide flat bottom, was not very deep and contains no lake sediments. Probably always a dry moat, providing material for the bank behind it. No Medieval finds.

Trench C: section through the deep inner moat.
Trench C: section through the deep inner moat.

Trench C in the inner moat demonstrated that this moat too had a wide flat bottom, but it was deeper and is full of hard clayey sediment: seems to have held shallow water. No datable Medieval finds.

Trench D: stone-filled cellar. Note the remains of the cellar's southern wall, right.
Trench D: stone-filled cellar. Note the remains of the cellar’s southern wall, right.

Trench D inside the inner defensive bank demonstrated that the site has been used for quite some time and rearranged: the stone pavement proved to be the top of a deep fill used to obliterate a rectangular cellar with drystone walls. Apparently this is the cellar of an early building that has been replaced by the large mortared masonry cellar that dominates the site today. It would have saved considerable labour to extend the cellar instead of replacing it, which suggests that this was the stronghold’s main building that couldn’t be torn down until its successor was habitable. Disappointingly, no Medieval finds in or under the stone fill.

Morning wait before we pile into the cars and go to the site.
Morning wait before we pile into the cars and go to the site.
Trench F demonstrated the same general trait of the site as trench D: there are two generations of two house foundations here, all in all four. No further Medieval finds after the glass shards and the coin.

Trench G at the northern end of the western line of buildings has given an iron latch lifter (that is, a simple key) and a spread of stones that suggests the building’s northern gable may have consisted of a drystone wall.

Let’s summarise what we’ve learned so far. Birgittas udde has quite a long Medieval use history where at least three buildings in the inner bailey have been replaced with newer versions. The high nobility makes its presence known not only through the fortifications and the large intricate masonry cellar, but also through a broken imported drinking glass. The complete absence of pottery in eight (or nine) indoor and outdoor trenches, though, suggests that waste management was quite fastidious, or that the site was never inhabited for very long each time, or both. This supports an interpretation where Birgittas udde is a special-purpose site for threatening situations, a fortified retreat in a peripheral location on Ulvåsa manor’s land. And the main Medieval version of Ulvåsa manor is at Gamlegården, the long-lived unfortified site abandoned in 1580.

A few decades ago a badger family dug a large sett next to the big cellar and dumped their spoil into it. The level floor left by the restoration architect in 1924 has had a big ugly spoil mound sitting in one corner ever since. At the landowner’s suggestion, and with the County Archaeologist’s blessing, my team rolled the turf off the mound and lifted it out of the cellar bucket by bucket to backfill the abandoned sett. Despite screening and metal-detecting much of the badger spoil, we made no Medieval finds. Another piece of restoration we’ve done is to give the intact piece of corridor vaulting over the cellar’s entrance a much-improved turf cover. This will keep rain from leaching the mortar out of the arch, improving its longevity.

On the 9th we’re moving our headquarters to Stegeborg camp ground & hostel. On the 10th a number of new team members will join to replace people who are only with us at Birgittas udde. And on Monday the 11th we break turf at Skällvik Castle. Stay tuned, Dear Reader!

First Week of 2015 Excavations at Stensö Castle

This year’s first week of fieldwork at Stensö Castle went exceptionally well, even though I drove a camper van belonging to a team member into a ditch. We’re a team of thirteen, four of whom took part in last year’s fieldwork at the site. All except me and co-director Ethan Aines are Umeå archaeology students. We’re excavating the ruin of a castle that flourished in the 13th and 14th centuries. This year we have a very nice base at Smedstad, let to us by the genial B&B host Hans-Ola. But we cook our own meals, each day having its designated cooks and dishwashers, and in the evenings we play boardgames.

The most outstanding result of the first five days’ work is that we found a runic inscription in the mortar on the outside wall of the castle’s south tower in trench E. There are five runes: three complete, one almost complete and one almost obliterated, enough to allow us to read helk(i), the male name spelled Helge in modern Swedish.

Helk(i): a runic inscription found on Stensö's south tower.
Helk(i): a runic inscription found on Stensö’s south tower.

This particular part of the tower wall was obscured by a pile of what we thought might be rubble from the torn-down western range of the perimeter wall. That occasioned the placement of the trench. Last year we found a stump of that wall sticking out of the north tower, and now we wanted to see it join the south one. The pile in trench E, however, turned out to be salvaged building material from when the castle was being quarried, apparently piled up here for removal but then left. There are several such piles in the bailey. We know that this quarrying happened a very long time ago, because the pile was full of neatly stacked re-used Medieval bricks that had crumbled in place. They are poor quality and can’t stand the annual dry-moist-freeze-moist cycle for very long. Since the brick pile was very old, we know that the inscription is even older. My good friend and colleague Christian Lovén judges that the quality of mortar from about AD 1200 is high enough that the inscription may be from the original erection of the south tower as a free-standing kastal structure.

Otherwise trench E has given lots of animal bones and a layer of stones just like in nearby trench B from last year. The stone layer looks like it was put there to raise and level the bailey after the perimeter wall was added. We hoped to get down to the base of the south tower to see what its footing on the bedrock looks like, but to our surprise we found that a deep part of the levelling layer to be sort of cast in concrete: a yellowish, finely laminated yet extremely hard calcareous material that looks like stalagmite. Apparently rainwater is leaching lime out of the south tower’s huge volume of mortar and redepositing it in the ground around the structure, effectively cementing stones together.


We placed trench D along the perimeter wall just north of the east gate because there are depressions there that may have functioned as rainwater basins. I was curious about what this wet environment may have preserved. Wise from last year’s experience of trench C, I laid the trench some ways out from the wall in order to avoid the thickest accumulation of rubble. And though the damp depression hasn’t yielded any macroscopic organics, a culture layer under the rubble has been quite generous with small finds: Hight Medieval Grey Stoneware, Late Medieval Red Ware with orange/green outside glaze, a knife, a whetstone, a strike-a-light, and best of all, a beautifully preserved copper alloy annular brooch. This last piece has a good parallel in the huge and securely dated Tingby in Dörby hoard from c. AD 1200 (thanks to my good friend and Fornvännen colleague Elisabet Regner for this).

Trench F is the badassest one of them all in terms of where it is: we’re digging half of the ground floor layer inside the south tower. Digging a kastal tower is an exclusive pleasure, and Ethan is making sure it’s being done well. Sadly we haven’t found any floor layer earlier than the one we stood on when we came to the site, but the rubble demonstrates clearly how the vaulting has come crashing down and is still in situ. The pottery here is the same Late Medieval ware as in trenches C and D, in addition to which we have two quite different crossbow bolts, a fish hook and other sundries. We’re of course searching eagerly for coins by means of metal detector and soil screening, but so far no luck.

At the foot of the castle hill outside the east gate is a rather flat, gently sloping surface that would be the natural place to land boats if you lived in the castle 700 years ago. Test pits there have so far given very recent waste, but more interestingly, also lots of flaked low-quality brick and mortar lumps. This looks like evidence for how building material was removed from the site during the post-aristocratic quarrying period. No reason to ship in used mortar.

I post this entry on Sunday night, eager for another week of fieldwork at Stensö. Stay tuned!

Turns out early-70s diesel trucks remodelled into camper vans don't have power steering.
Turns out early-70s diesel trucks remodelled into camper vans don’t have power steering.

2014 Castle Excavation Reports

Last year I headed four weeks of excavations at two previously unexplored castle ruin sites near the Swedish city of Norrköping: Landsjö in Kimstad and Stensö in Östra Husby. Finds and written sources suggest that both were built and inhabited in the 13th and 14th centuries. All known owners were members or close relatives of the powerful Ama family. Now Ethan Aines and I have finished the archive reports, available here on ScienceBlogs [Landsjö and Stensö] and on Rudolf Gustavsson’s osteological reports (in Swedish) are included. Comments and questions are most welcome! We will resume fieldwork five weeks from now.

Guest Digging At Birka

When I tell people I’m an archaeologist, they often ask ”So have you dug at Birka?”. As of yesterday I can finally proudly reply ”yeah, a bit”.

”Birka” is a Latinate attempt to write Biærkey, ”Birch Island”. It’s an island in Lake Mälaren, two hours by slow boat from Stockholm. For a bit more than 200 years starting in the mid-8th century, it hosted the first town on Swedish soil, established there as a regulated international trading post under the protective (and probably tax-grabbing) hand of the Kings of the Swedes. This immortally classic Viking Period site has huge cemeteries, a huge early urban culture layer which is up to two meters thick, a town rampart, a fortified hilltop and more.

My friend Sven Kalmring and his team have reopened and extended the trench excavated in 1969–71 under Björn Ambrosiani’s direction, in order to learn more about Birka’s waterfront during three weeks of fieldwork. Tuesday my friends Roger Wikell and Kalle Dahlberg visited them and managed to find a chunk of a runestone sitting in a clearance cairn near the trench. And Wednesday I paid a visit.

Getting to Björkö is difficult if you don’t want to spend hours on the tourist boat and you haven’t got a boat of your own. The closest point you can drive to is Lindby dock on the southern tip of Adelsö, whence you can see the town site clearly. Unless you want to swim 300 metres though, you somehow have to find a boat. I was helped by Runemaster Kalle Dahlberg, who very kindly lent me his canoe. He taught me to put stones in the prow box to keep from drifting sideways when paddling solo in a strong wind. And soon I was at the trench edge on Björkö, saying hi to my peeps.

When visiting someone’s dig for just a few hours, I try to make myself useful in capacities that don’t require any time-consuming teaching, and where I won’t mess stuff up. I spent the day hauling buckets of water out of the trench (there’s a feckin’ stream running through the deeper parts of the trench, sandwiched between the fat culture layer and the equally fat post-glacial clay under it), delivering them to the screens, and wet screening bucket after bucket of the Black Earth. I’ll say that again. Wet screening the Black Earth of Birka. If you’re into small finds, this is as good as it gets.

The Black Earth is full of well preserved bones and teeth of animals, including loads of fish bones, even a piece of swan eggshell in one of my buckets. It reminded me of the Thames foreshore at low tide. I also picked up quite a quantity of burnt clay and knapped stone, and some 19/20th century bits from the top layers. My best finds of the day were a 6 mm globular rock crystal bead and a small cupped piece of yellow/green vitrified clay. This latter looked like a piece of either a crucible or a Schmelzkugel, the brazing packages used when making brass-covered iron weights.

Runologist Magnus Källström visited and gave Roger’s & Kalle’s runestone fragment some tender attention. With his expert pointers and my own examination I got the impression that the fragment reads iruasaþ, but I have no idea what that might mean. It’s certainly not one of the region’s many formulaic 11th century inscriptions. Magnus is a popular guy right now. Marta Lindeberg’s team found a beautifully carved rune bone with a long inscription at nearby Sigtuna, Tuesday.

At four I got back in Kalle’s canoe and paddled back to Adelsö, with the soot of the Black Earth under my nails, red-pated from the May sun, and with a song in my archaeologist’s heart.

How I Select The Sites I Dig

Having read yesterday’s entry about what I need to get hold of before I can dig a site, Apel Mjausson asked me on Facebook, “How do you decide where to dig? Sweden is lousy with unexplored sites. Are you following a specific story, looking at place names, take nominations…?”

Disregarding sites I’ve been paid to dig and sites I’ve only metal-detected,* my motivations have been as follows. To begin with, I only ever dig sites that I judge likely to produce something publishable and exciting. (And sometimes I lose on that gamble).

  • At Barshalder in 1997 I dug two graves because at my advisor’s suggestion I was writing my thesis on a huge cemetery, and there were a few sections of it that nobody knew anything about.
  • At Skamby in 2005 Howard Williams and I dug a boat grave because our friend local historian Arne Danielsson suggested it, because boat inhumations are famously rich in well-preserved artefacts, and because nobody had dug a boat grave in Götaland before.
  • At Stora Tollstad in 2006 Howard and I trial-trenched a major barrow in order to date it and find out if it was relevant to my on-going work with the late 1st millennium. (It was.)
  • At Sättuna in 2008 Petter Nyberg and I stripped 1047 sqm in a field because metal detector finds suggested that the postholes of a Vendel Period elite manor were sitting under it. I had metal-detected the site because it has another huge barrow and a name ending in -tuna, which signals the presence of power in the 1st millennium. Sadly the landowner wouldn’t let us at the most promising field because of a crop, so we dug in the second-best one next to it and found nothing to write home about.
  • At Pukeberget in 2011 Margareta Backe and I dug a few test pits in a cave because a Bronze Age spearhead had been found inside, I was writing a book on Bronze Age deposition sites and I wanted to know if there was more evidence of ancient activity in the cave. We found only recent cub scout stuff.
  • At Stensö and Landsjö in 2014 I dug a number of trenches in two castle ruins because I hadn’t worked with the High Middle Ages before, I wanted to study castles and Christian Lovén suggested these two sites. They are the only castles in Östergötland that have perimeter walls despite being owned by the nobility rather than by the Crown or Church. Neither had seen documented excavations before.

* For some reasoning around 1st millennium AD candidate sites for metal detecting, see pp. 16-17 in my 2011 book Mead-halls.

What I Need In Order To Dig My Sites

I’ve headed my own research excavations since 1996. Now I’m preparing for four weeks of fieldwork during the upcoming season. I operate as an independent scholar in this context, and none of my excavations have been prompted by land development. Here’s what I need to get hold of before I can break the turf or metal-detect the plough soil on an archaeological site in Sweden.

  • Contacts/notoriety. I couldn’t get much of what’s listed below without contacts/notoriety in the business.
  • Funding. Most of my research money comes from small private foundations in annual instalments of about $3,600 (€3,200 = SEK 30,000). The most dependable ones have supported my work for 20 years and seem pretty confident that I’ll do something useful with the money.
  • Land owner’s permission. I check the property name on the map, then I call the municipality’s land registry to find out who owns the land, and then I call the owner and ask. So far nobody’s said no, though one or two first wanted to know if they might be hit with any costs. They never are since they’re not the ones who head the digs.
  • An organisation to apply for the excavation permit. A person can’t get a permit. Only organisations can. I always collaborate with the county museum. We make an agreement where they will apply for the permit, and I promise that no costs will hit them. This is an expression of generosity and trust on their part, motivated to some extent by scientific curiosity. Unlike highway contract archaeology, I tend to target the most interesting sites around that my colleagues have wondered about for years.
  • County Archaeologist’s permission. I write a permit application, my colleagues at the museum tweak it a bit, and then they send it on to the county council. The County Archaeologist only gives us a permit if I’ve written up my previous fieldwork and if it seems likely that I will be able to pay for finds conservation.
  • Labour. I work with volunteers: students, metal detectorists, the members of local historical societies, friends and family.
  • Equipment. I borrow most of the fieldwork equipment from the county museum and other contract archaeology units.
  • Housing. Unless the participants in the dig live near the site, I have to provide housing. Just after lunch today, for instance, I called the Östra Husby village grocery store and got the number of a man who lets a house not too far from Stensö Castle. He was surprised to hear that I need twelve beds, but adapted quickly and said that he’ll be happy to find the extra ones for me.