: Archeoleg

Mae ein neuadd ganoloesol yn codi’n gyflym. Mae'r gwaith yn canolbwyntio ar orffen ffenestri yr adeilad lleiaf o ddau. Adeilad B yw'r enw dros dro am hwn, ac yn y gorffennol fe allai wedi bod yn siambr wely’r tywysog (gan fod enghreifftiau eraill o neuadd a siambr gyfagos yn bodoli) neu yn gegin, a fyddai hefyd yn debygol o fod yn agos i'r neuadd (oherwydd pwy fuasai am wledda ar fwyd oer?).

Mae'r ffenestri yn Romanésg eu harddull, sy’n nodweddiadol o'r cyfnod. Yn gul ar du allan yr adeilad ond yn lledaenu’n sylweddol ar y tu fewn, mae’r cynllun yn manteisio i’r eithaf ar y golau naturiol. Mae dau reswm pam eu bod mor gul: mae ffenestri bach yn haws yw hamddiffyn na ffenestri mawr, ac felly roeddent yn elfen gyffredin mewn adeiladau amddiffynnol fel cestyll; ac yn ail, gan bod gwydr ffenest yn gymharol brin yn y cyfnod roedd ffenestri bach yn lleihau’r drafft oer a allai ddod i mewn. Carreg wastad sydd ar ben bob ffenest, ond gallai hefyd fod yn fwa cerrig – roedd y naill ddull yn gyffredin yn y cyfnod. Mi fydd caeadau pren dros y ffenestri i’w cau pan fydd plant ysgol yn aros dros nôs.

Yn ogystal â'r gwaith cerrig, mae'r gwaith o lifio pren i ffrâm y to wedi cychwyn yn ddiweddar hefyd. Camp grefftus tu hwnt yw ffurfio darn pren sgwâr o gainc coeden dderw. Dim ond mewn llinell syth y gall y 'band-saw' dorri, felly mae'r gainc yn gorfod cael ei lleoli yn union cyn cychwyn y gwaith llifio. Mae angen ei addasu i lan ag i lawr, yn ogystal ag i'r chwith ag i'r dde, oherwydd gall un toriad gwael effeithio ar y toriadau dilynol i’r fath raddau nes bod y darn pren yn annefnyddiadwy.

Rwyf newydd gychwyn fy mhedwaredd wythnos fel Prif Guradur Adeialdau Hanesyddol yma yn Sain Ffagan, a dyma fy mlog cyntaf. Archaeoleg yw fy nghefndir, ac yn bennodol, archaeoleg arbrofol.

Mae’r math yma o ymchwil archaeolegol yn arbrofi’r syniadau sydd wedi tyfu fel canlyniad o waith cloddio archaeolegol. Yn y bôn rydym yn trio codi rhywbeth a fyddai yn gadael yr un tystiolaeth a ddarganfyddwyd, os cloddiwyd yn y dyfodol. Mae hwn yn herio ein syniadau a codi mwy o gwestiynau.

Tai Crwn o'r Oes Haearn

Dros y blynyddoedd rwyf wedi adeiladu pedwar tŷ crwn wedi seilio ar archaeoleg cartrefi Oes yr Hearn. Gan bod yr archaeoleg yma yn gallu bod yn fâs iawn (ond rhyw 30cm o drwch), mae pob elfen o ail-greuad uwchben y ddaear wedi’i seilio ar waith dyfalu – ei hun wedi seilio ar y dystioilaeth sydd wedi goroesi. Fel allech ddychmygu, mae gweithio allan strwythur adeilad sydd heb yw weld mewn 2,000 o flynyddoedd yn eitha sialens, ond un boddhaol. Felly, mae gen i bleser mawr i fod yn rhan o gyweithiau arbrofol newydd yr Amgueddfa - ailgreuad o ffermdy o Oes yr Haearn, wedi ei seilio ar dystiolaeth o Fryn Eryr yn Ynys Môn, a neuadd ganoloesol Llys llywelyn, wedi ei seilio ar dystiolaeth o Llys Rhosyr, eto yn Ynys Môn.

Mae tô y ffermdy yn cael ei doi gyda gwellt ar y funud, ag yn fuan mi fydd y tŷ yn ddiddos. Mi fydd hwn yn rhyddhâd mawr gan bod glaw trwn dros y Gaeaf wedi atal y waliau clai, 1.8m o drwch i sychu mor gyflym a gobeithio. Mae waliau o glai yn gymharol anarferol gan taw waliau gwial a dŵb neu cerrig sydd wedi eu darganfod gan amlaf. Hwn fydd yr ail-greuad cyntaf o dŷ crwn o’i fath.

Llys Rhosyr - Llys Canoloesol

Mae waliau y ddau adeilad sydd o’r Llys mor uchel a fy mrest, ac mae’r saer maen yn barod i gychwyn y fframau ffenestri. Fe ddarganfyddwyd y Llys yn Ynys Môn, ac fe’i gloddiwyd rhwng 1992 ag 1996. Mae’r waliau cerrig ond yn sefyll ryw fetr o daldra. Felly, yn yr un modd a’r ffermdy, ail-greuad wedi seilio ar dystiolaeth archaeolegol yw hwn.

Mae hanes ysgrifennedig o’r cyfnod, fel ‘Brut y Tywysogion’ yn awgrymmu fod neuadd frenhinol yma, a fu yn un o Lysoedd Llywelyn ap Iorwerth yn ystod hanner cyntaf y drydedd ganrif ar ddeg. Y peth dydyn ni ddim yn gwybod gyda sicrwydd yw pa olwg oedd ar y neuadd. Mae’r wybodaeth yma wedi ei seilio ar gymhariaethau gyda neuaddau Brenhinol eraill, ag adeialdwyd yn yr un cyfnod, fel a welid yng Nghastell Conwy a Phalas yr Esgob yn Nhŷ Ddewi.

Gan fy mod yn bwriadu ysgrifennu blogiau cyson ynglyn a’r datblygiadau diweddaraf, fe wnaf anelu hefyd I amlinellu y gwaith sydd wedi digwydd hyd yn hyn, felly fydd genych fwy o syniad ô’r adeilad hynod yma, ac ein ymgeision i ddod ar Llys yn fyw unwaith eto.

As Steve said in his last blog posted in December, we’ve started work on growing the thatch for our new Iron Age farm. Alongside this work we’ve also been giving a lot of thought to the objects that will go inside the houses.  Far from being primitive, these replica objects will reflect the high level of knowledge and skill possessed by people who lived in Bryn Eryr over 2000 years ago. One of the first tasks is to furnish the round houses with all those essential objects that no self-respecting Iron Age household could do without, such as plates, bowls, utensils, buckets , storage containers, shelves, barrels, weaving looms, beds, just to name a few.

In this period all these items were made from wood, but we have a problem, wood deteriorates quickly in the ground so objects made from this material rarely survive.  However, we think we can find out more about the wooden objects they would have had by studying the carpentry tools available at this time. These were made from iron and because of this have survived in greater abundance. Ancient iron-work is often much underrated as it doesn’t look very attractive, but when trying to recreate everyday life the information domestic ironwork objects can provide is invaluable.

The first stage of making the replicas was to search the archaeological collections for any original Iron Age carpentry tools.  Much to my delight we had quite a lot of material and could virtually recreate a whole tool kit from examples found throughout Wales. Our Bryn Eryr tool kit will therefore consist of an axe, adze-hammer, gouge, chisels, files, drill bits and numerous wedges from small to large.  Timber in the Iron Age was divided up by splitting with wedges rather than cutting with a saw.  Saws did exist, but were small, similar to modern pruning saws today.

An Iron Age household would be equipped with a wide range of tools for a variety of purposes. Some of these objects appear strange to us today, but others are quite familiar. A 2,000 year old chisel found in the Roman fort of Brecon Gaer and a gouge from the Hill Fort at Castell Henllys wouldn’t look out of place in a carpenter’s tool kit today.

Once our tool kit had been compiled from the examples in the collection, the next step was to make working replicas that could be used by our craftspeople to recreate the objects for Bryn Eryr.

Careful conservation of the original tools had preserved some of the original surfaces. Marks on these surfaces enabled our blacksmith 2000 years later to work out how they were made and reproduce the replicas as accurately as possible.  The replicas are recreated in wrought iron like the originals, which is much softer than the steel used today, so it will be interesting to see how these tools perform? Will we be able to produce a decent cutting edge, how quickly will this edge dull and how often will it need to be sharpened?

Making the tool heads is only half the story, these tools can’t be used without handles!  None of the originals survive and from the shape of some tools we just can’t pop modern handles on them.  We know our tools once had wooden handles, because in some cases the deteriorating iron around the socket  had made a cast of the wood surface before the handle disappeared.  Using a combination of this information and some surviving material from elsewhere, plus the expertise of our own carpenters and estate workers, we managed to reproduce handles to complete the tools.

Now all we have to do is see if they work! More importantly have we still got the expertise to use these tools properly? Hopefully by using them we’ll gain an insight into the skill of our Iron Age carpenters.  I’m sure they would be laughing themselves silly if they could see our efforts today, but we have to start somewhere!

So, how did our tools perform? Its early days, but everyone including our craftspeople are impressed. They appear to be performing well, we even managed to split a large piece of timber with our wedges.  It probably explains why so many of these wedges end up in our collection, they tend to get lost inside the timber during splitting and fall to the ground where they are difficult to spot!

We hope to undertake more experimental work to assess the performance of these tools, so keep watching this space, but in the mean time we have to crack on, there’s the contents of a roundhouse to make!

As many regular visitors to St Fagans will know, our much-loved Celtic Village was closed earlier in the year. Twenty years seems to be about the normal life-span for reconstructed Iron Age roundhouses – the timbers decay and they begin to get a bit wobbly after that. To replace it we're going to be building a new reconstruction based on a 2,000 year old Iron Age farmstead on Anglesey called Bryn Eryr, and just recently we reached a really exciting milestone along the way.

The Bryn Eryr roundhouses consisted of two buildings built side-by-side. Their walls were made of packed clay (probably mixed with grit and straw, like Wales's traditional clom-built houses) and the roofs were thatched. We've had a lot of discussions about what we should use to thatch them. Naturally the roofs of the original buildings haven't survived, but we do know that its Iron Age owners had access to spelt – an early form of wheat – because charred grains were found at the site. From there the argument goes, if they were harvesting spelt grains to make their bread they also had their hands-on a useful thatching material, spelt straw.

So, we thought, St Fagans is surrounded by farm land, we've got an excellent farming team, and lots of enthusiasm, why not try to grow a crop of spelt ourselves and see whether we can thatch our next Iron Age farmstead with it?

There are a lot of uncertainties involved in this, many things can go wrong between the idea and the harvesting but St Fagans is part of an EU collaboration which encourages just this kind of experimental research. So thanks to the OpenArch project, with its Culture programme funding, and a lot of advice from experts in the field (apologies for the pun), we've decided to give it a go.

A few months ago we ploughed 3.4 hectares (8.4 acres) just outside the main museum site. This looks like an enormous area when you're stood beside it, but we're told this is what we need in order to produce enough straw to thatch two large roundhouses.

With the ploughing done, our Learning Team organised an opportunity for school groups to come out and see what we were up to. This was followed by the museum's archaeologists bringing together a team of volunteers who walked the area in search of any artefacts that may have been turned up by the plough. The finds from this have yet to be analysed but already we can see that the area had been visited by prehistoric hunter-gatherers, a 13th-century traveller who lost some loose change, and many other more recent people.

And then it rained, and rained and rained. Our spelt seed arrived and was placed in a barn, and still it rained. I was beginning to get very worried. It's all very well having a plan to grow a crop of Iron Age wheat, but that's not going to happen if the seed stays in sacks. Then a few weeks the weather cleared up, the ground dried sufficiently and we finally got a chance to plant.

Then we waited… Would anything happen? Had we left it too late? Would frosts / rain / snow put a stop to our plans? Happily not! Last week we found the first seeds had germinated. I’m going out to the field again today to check on its progress. Will the shoots be showing? Have we got the spacing of the seed right? Will the rabbits leave it alone? Will it grow tall? I feel like an expectant father all over again.

One item currently residing in the archaeological conservation laboratory is something that looks like a pot, but isn’t!  It’s solid and actually made of soil that contains the cremated remains of a Roman who once lived at the Roman fort of Isca, now the town of Caerleon. This was contained inside a pot, but  the vessel was cracked and broken so the pieces fell away leaving it's contents intact, held together by the dry clay soil.

Wherever you dig in Caerleon you often find the Romans have been there before you. So, not surprisingly, when digging the foundations of a garage a cremation urn was unearthed. The pot and contents was carefully excavated and brought back to the conservation lab at the National Museum of Wales in Cardiff for examination and treatment.

Once the soil had been removed from the outside it became clear the pot was seriously damaged. In damp ground this relatively low fired pottery becomes quite soft and therefore easily misshapen by the pressure of the soil around it. The building work above had squashed our pot forcing the rim and shoulders down inside it, while the sides had begun to bulge out and split like the segments of an orange. It was only the soil around the pot that was keeping it together, so as the soil was carefully removed in the lab, pieces of the pot (in archaeology referred to as pot sherds) started to fall away leaving a complete pot-shaped core of soil still containing the cremation. It even had a cast of the interior surface, including the ridges created by the potter’s fingers formed when the clay was being turned on the wheel.

Once the pot was fully dismantled and cleaned, all 105 pieces were put back together again, some areas were missing and hadn’t survived, but enough was retrieved to recreate the original shape. The pot was a bit reluctant at first to return to its original form because it had become misshape in the ground, but with gentle persuasion and patience it was successfully reconstructed, this did take a few days though.

The surface of the pot was also very powdery and every time it was moved or picked up it left a patch of orange powder behind. To stop further loss the pot had to be treated with a very dilute adhesive to help consolidate the surface, allowing it to be handled safely again.

When new the pot may not have looked orange, but white! There is evidence to suggest cremation vessels may have been coated on the outside in a white clay slip. The surface of our pot was too damaged unfortunately to say if that was the case here.

Was the pot an everyday storage jar selected to contain the cremated bones or was it made especially for the purpose? This question still intrigues archaeologists today, in the case of our pot the rim was badly damaged, but what survived was not the plain rim normally expected on domestic pottery, but a slightly indented, impractical frilly edge which might suggest it was especially made for the purpose. More evidence is required before we can be sure though.

The next stage is to excavate the soil block and retrieve the cremated bone and see if any objects were placed in the pot with the remains.