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.

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Stensö castle, trench C, the part along the perimeter wall. Note the ashlar. Drove down to Vikbolandet on Sunday night with my excellent colleague Ethan Aines from Stanford, and we were met at expedition HQ by seven of my Umeå students from last autumn semester. Very pleased to see them again!…
After four days of rubble removal in trench A, we found the south wall of Stensö Castle's northern tower. Note how the wall facing (left) ends, and a pale mass of wall core (lower right) emerges out of the tower. This is the castle's previously unseen western perimeter wall. Our first week of…
Christian Loven's plan of Landsjö Islet with letters marking on-going fieldwork. Landsjö castle is on a high islet in the lake next to the modern manor house. Nobody ever goes there. The ruins are covered by vegetation and they're in bad shape: only along the western side of the islet do they…
Balancing available labour and a pre-decided excavation agenda against each other is not easy, particularly when you're doing investigative peek-hole fieldwork on a site whose depth and complexity of stratification you don't know much about. At Stensö we had two of three trenches and all five test…

*Is* "badassest" a word?

Has everybody heard
about the bird
-I wonder if the builders had the sense to dig a well as far away from the "waste" deposit sites as possible.

Useless factoid: Helge/Helga eventually became Oleg/Olga.

Jane, are you in need of reading material for the vacation?

By birgerjohansson (not verified) on 29 Jun 2015 #permalink

The inscription is in a highly visible spot so I'd say the guy was a bigwig. Runic inscriptions on secular buildings are exceptionally rare, probably because well-preserved ones from the 12th and 13th are so rare.

Keep hydrated during the dig! There is some Australia-grade hot weather coming.
BTW remind the Umeå students to pay a visit to the rapids in Umeå river, while the spring flood is still allowed to bypass the dam. Impressive!

By BirgerJohansson (not verified) on 02 Jul 2015 #permalink

Of course the newcomers must learn the local language. Otherwise they will think they own the land. Just ask the Sámi people...

By Lassi Hippeläinen (not verified) on 02 Jul 2015 #permalink

Otherwise they will think they own the land. Just ask the Sámi people…

According to an apocryphal story told in the US, the First Nations chief for whom the city of Seattle was named is claimed to have advised then-President William Taft: "Watch your immigration laws."

By Eric Lund (not verified) on 02 Jul 2015 #permalink

I speed-read Birger's post too quickly and got "So secular people kept using iTunes..."

And the only tennis player who complained about the heat at Wimbledon was Bernard Tomic, who comes from Darwin. But then, he has a bit of a record.

By John Massey (not verified) on 02 Jul 2015 #permalink

@John: But heat in tropical cities near the coast is often not as intense as at inland and temperate locations--much of the inland Pacific Northwest has had temperatures of 40-45 degrees in the last week (there is a not-yet-confirmed report of 46 degrees from an automated station in Idaho), while Miami's international airport has never recorded a temperature above 38. This is a major reason why people like to visit seaside or lakeside resorts in the summer months. Also, you may have heard of a group comprised of mad dogs and Englishmen. There is a reason Mediterranean and Latin American countries developed the tradition of the siesta. Even at my temperate latitude, I avoid early afternoon gardening work during the summer months. And remember, buildings in the UK are designed to keep people warm, not cool.

By Eric Lund (not verified) on 02 Jul 2015 #permalink

Eric, sure, but Tomic is just a prima donna. Kyrgios is the same. The only one of them worth anything is Kokkinakis. And Lleyton Hewitt, who lost his 5 set match without a murmur about the weather conditions.

Tomic was bitching because the women get a 10 minute break between sets when it's that hot, the men don't. Reason? The WTA asked for it, the ATP didn't. And as Petra Kvitova has finally pointed out in public (oh the horror), women menstruate, which can make it tough for them - not to mention potentially embarrassing when they are playing in all-white clothing in front of a TV audience of millions.

The temperatures this week are unusual for Wimbledon, but they are nothing like the temperatures that the players experience in the Australian Open.

By John Massey (not verified) on 02 Jul 2015 #permalink

But was there any reason to ship *out* used mortar? Or was it just there because it was adhering to the bricks?

By John Massey (not verified) on 02 Jul 2015 #permalink

I'm thinking it's likely to have dropped off the stones & bricks. It's not enough to represent mortar mixing on the spot.

If the mortar was made at the same time as the Visby city wall, it is likely to have been made in a similar way, with reservations for dissimilar local ingredients.
Restoring that wall with the wrong kind of mortar was a costly mistake -has anyone worked out a close analogy for the old medieval mortar yet?

By BirgerJohansson (not verified) on 03 Jul 2015 #permalink

Mortar is just sand sized particles mixed with something that has some pozzolanic action, like ground up volcanic ash or pumice mixed with lime, so that when the mixture is mixed in the right proportions with water it is workable so you can spread it onto the bricks, and then it undergoes a chemical reaction so that it hardens into a cementitious material, hopefully without expanding or contracting too much as it dries, and adhering reasonably well to the bricks, although chiefly it is required to act in compression.

My guess is that, if no one has managed to replicate the old medieval mortar, it is because the original source of pozzolana has been worked out and it is no longer available.

The concrete used in ancient Rome was superior to modern concrete for the same reason. All the pozzolana they used has been used up.

It sounds like the mortar used for restoration had a coefficient of thermal expansion that was too different from that of the bricks, so it would not adhere to the bricks and the wall would crack along the interfaces between the mortar and the bricks. With repeated cycles of heating and cooling, the wall would actually fall apart.

Someone needs to find a deposit of volcanic ash somewhere that was similar enough in composition to the original deposit used in medieval times, and then replicate the proportions of sand, lime and pozzolan that was used (if indeed they used any sand in the mix).

By John Massey (not verified) on 03 Jul 2015 #permalink

#16 My daughter likes to watch attacking mid-fielders like Frank Lampard who can score goals from outside the box. She thinks hitting a goal from distance is the most beautiful thing.

I once commented that Frank is quite good looking. She looked surprised that I would make that comment - I honestly don't think she had noticed. She just admired his skill. She played a bit of football at school; enough to know how hard it is to do that.

Yes, projection. A lot of women watch football because they like watching football.

By John Massey (not verified) on 03 Jul 2015 #permalink

Since Hagia Sofia has been resistent to the many earthquakes to hit the city, the Turks have better find some deposit that mimics the ancient source closely....
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(OT) Mapping the people of Scotland

By BirgerJohansson (not verified) on 03 Jul 2015 #permalink

It depends on the foundation it is built on - some ground amplifies earthquake motions, other ground dampens them. Maybe the builder of Hagia Sofia got lucky and built it in the right place.

Turkey has a lot of untied masonry structures, which perform very badly in earthquakes. Brick and masonry structures need steel ties to make them earthquake resistant; otherwise they are liable to catastrophic collapse.

By John Massey (not verified) on 03 Jul 2015 #permalink

It depends on the foundation it is built on – some ground amplifies earthquake motions, other ground dampens them.

Places where fill has been used to raise the ground level are particularly vulnerable. That was a contributing factor in the motorway viaduct collapse in Oakland due to the 1989 earthquake. It didn't help that the structure in question was a double-decked bridge. They finally reopened that motorway almost a decade later, on a different alignment, as a single-deck structure. Another Bay Area motorway, the Embarcadero Freeway, was closed permanently after that earthquake--it ran along a portion of San Francisco's waterfront just east of the financial district.

The place I live now is built on bedrock, so when relatives from outside the area asked me two or three years age if I felt the earthquake (the one in Virginia), my reaction was, "What earthquake?" But during my undergraduate years I lived in a place that was on a filled-in part of what was once the Charles River. While I was there I felt an earthquake that was centered a few hundred kilometers north of Quebec City.

By Eric Lund (not verified) on 03 Jul 2015 #permalink

The city of Perth in Western Australia is built largely on old dune sand deposits, which in places have become indurated into sandstone (the ideal material for damping earthquake motions), and alluvial clay deposits from the Swan River that flows through the city.

When I was an engineering student, I experienced an M6.9 earthquake centred near the town of Meckering 130 km away from the Perth CBD. The only buildings in the Perth area which suffered any significant damage were those founded on the alluvial clays, and some of the older multi-storey buildings which could not tolerate differential movements without cracking, but they were all repairable; none required demolition and rebuilding.,_Western_Australia

This was a really unusual experience - I was upstairs in a two storey house that we lived in at the time, studying. I heard a 'rushing' noise, got up to look out the window and saw big trees in the distance being shaken to and fro, and then I could see sinusoidal ground motions like waves on the sea, but translational, not just rotational, moving straight toward me (they were moving straight toward everyone because they were radiating out from Meckering). I knew what it was, and remember saying to myself "Those movements are going to hit me...right" And then the floor began bouncing up and down so violently that I was thrown to the floor. I was down on the hardwood floor on my hands and knees, and the floor kept coming up and hitting me in the knees painfully hard. It lasted for 40 seconds, but seemed a lot longer - my sister was in the next room screaming hysterically because she had no idea what was happening, and I was trying to get to her to get her downstairs and outside. I needn't have bothered - by the time we got outside, it was all over, although there were some fairly faint aftershocks. My sister laughs when she talks about it now - she claims when I got to her I said "It's OK, it's just an earthquake."

Being a conscientious engineering student, I carefully inspected every square inch of the walls and ceiling of that house afterwards - I couldn't find a single crack anywhere. The few buildings that suffered substantial cracking were those built close to the river, on the alluvium. Houses in Perth are constructed of double brick, with steel ties, so there were no building collapses in Perth at all, even though the earthquake was strongly felt. If most buildings had not been founded on dune sand or sandstone, there would have been a lot more building damage.

The total casualty count from that earthquake was one guy in Meckering who got a broken leg - he was up a ladder when the earthquake hit and he fell off the ladder. The whole town was totally demolished, and an earthquake scarp was formed which was up to 3 metres high - it cut the road into town completely, which had to be regraded. Parts of the scarp are still visible now.

A shallow M6.9 earthquake like that hitting a town in Turkey would result in multiple collapses of untied masonry structures, probably with quite high loss of life. In that scenario, a lot of fatalities are caused by masonry falling or collapsing on people.

By John Massey (not verified) on 03 Jul 2015 #permalink

John, I do not think that Roman marime concrete is a great mystery or that the original pozzolana has been used up. John Oleson in Victoria has taken many samples of original pieces for his ROMACON project, and made a 2 x 2 x 2 metre block which is sitting in an Italian harbour being periodically drilled and tested to see how it cures.

By Sean Manning (not verified) on 04 Jul 2015 #permalink

Sean, interesting. No, not a mystery, but impressive.

Is there a reference you can give me?

By John Massey (not verified) on 04 Jul 2015 #permalink

John, I expect that you can google as well as I can. I got what I know about this project in person.

By Sean Manning (not verified) on 05 Jul 2015 #permalink

I did google, but I have only so much time to spend sifting through irrelevant stuff.

By John Massey (not verified) on 05 Jul 2015 #permalink

Bother ... I thought I had given good keywords, but here is Dr. Oleson's website with a bibliography and several of his articles in HTML Like Martin he has been on the web a good long while so most of his site is plain HTML.

By Sean Manning (not verified) on 05 Jul 2015 #permalink


By John Massey (not verified) on 05 Jul 2015 #permalink