What lies beneath: what a ground penetrating radar survey reveals of Druminnor Castle

Lead Archaeologist on the Druminnor Castle excavation, Dr Colin Shepherd, looks at the results of the ground penetrating radar (GPR) survey of the castle in funded by the Castle Studies Trust in 2019 and what that means for future work at the site.

As a consequence of the GPR geophysics, that were generously funded by the Castle Studies Trust, we have a number of new and potentially interesting anomalies to be investigated. Furthermore, the GPR research has also been instrumental in clarifying other aspects of previously excavated evidence. This has been made possible as, contrary to most instances, the geophysics at Druminnor have been incorporated into the ongoing investigation rather than simply as a precursor to excavation.

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The GPR generated 286 ‘radargrams’ or sections across the site and much time and effort has gone into analyzing these. The radargrams were compared to actual excavated sections. This permitted the creation of a ‘key’ that has allowed us to extrapolate from the excavated sections to unexcavated parts of the site. As a result, we can, fairly comfortably, suggest a developmental plan of Druminnor spanning the 13th to 18th centuries (Figure 1).

Suggested phasing of Druminnor Castle by Colin Shepherd

The GPR has suggested the extent of a hardcore platform that appears to have supported the ‘Old Tower’. This was thought to have been the earliest part of the castle but without hard evidence. We hope to test the presumed limit of this platform as we extend our trench southwards from the well that sat within the tower. (As you will recall, the GPR alerted us to that remarkable feature that became a focus for our 2019 season.) The GPR suggests that there may be a revetment supporting the platform at that point. Also, any relationship between this platform and the mid 12th-century kiln will be important in attempting to date that platform and, by extension, the Old Tower itself.

Well found in tower as a result of the GPR survey

The radargrams have also demonstrated the probable line of a terrace and sunken formal garden (red hachures on plan) and permits the excavated section of revetment and steps (shown in black) to be placed in its proper context. This garden probably dates to the 16th or 17th century, though exactly when is still debatable. The construction of the terrace removed all trace of the earlier (early to mid 15th century) ditch and so must post-date that. A late 17th-century Dutch pipe bowl found in the fill of a post hole associated with the steps suggests its removal at around that time or shortly thereafter. No trace of the terrace appears on the estate plans of c.1770.

The line of the defensive ditch has been shown by the radargrams to extend westwards from the excavated portion in Trench 11. This gives us an accurate alignment permitting its course to be drawn, even though the middle section was removed by the terrace. Where its return is at the western end of the site is still a mystery. The eastern arm was excavated in Trench 2 lying beneath the later (early 16th-century) lower courtyard. The 15th-century upper courtyard incorporated the tower with the surviving hall block (shown in blue). The courtyard’s west range can be estimated from remains found during the kiln excavation, but its eastern boundary was removed when the lower courtyard was added.

Finally, the GPR revealed the line of the outer enclosure wall as depicted on the estate plans. This was sampled in 2019 and the base of the wall found. The date of this feature is presently unknown and further work needs to be done to try to clarify that matter.

Evidence of landscaping material in outer enclosure copyright Iain Ralston

Sadly, work planned for 2020 included the extension of the ‘well trench’ in the car park to look for the possible revetment suggested by the GPR as well as opening a much bigger area across the outer enclosure wall, as located by GPR. This sits beneath a good metre and a half of later landscaping material (see picture, courtesy of Iain Ralston) and, for safety and archaeological reasons, demands a much larger trench. The keyhole sample trench indicates good survival and, it is hoped, evidence will be found to date the feature and to help explain when this became the northern boundary of the castle enclosure.

The excavated evidence together with the GPR results permit this developmental plan to be made and rough dates affixed. It is worth noting that, prior to our investigations, Druminnor was believed to have consisted solely of the surviving hall block with an attached tower at its western end. Everything not in blue on the plan, therefore, was formerly completely unknown.

Access in 2021 is still, sadly, in the laps of the Gods owing to Covid, but it is hoped that we will be able to get back on track later this year to look for more goodies!

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‘All Along the Watchtowers! Balancing Heritage Protection, Development, and Scientific Research on Buried Archaeology at European Castles’

Dr Rowena Banerjea, University of Reading, UK, with funding from a British Academy/Leverhulme Small Research Grant talks about the research project she works on All Along the Watchtowers! https://research.reading.ac.uk/castle-geoarchaeology-heritage/

The buried or below-ground archaeology at castle sites can be exceptionally well preserved because of its burial under masonry. However, it is often overlooked in conservation and management plans in favour of protection and consolidation of standing remains and developments such as reconstruction and rebuilding projects. It provides an important lens through which we can examine important phases and hiatuses in the developmental history of these monuments.

INSERT FIGURE 1. Well-preserved stratigraphy at Château de Gien, France, from c. 9th – 11th AD occupation, sealed below later masonry and collapse. The rectangles show where micromorphology samples were collected, and the circles mark the locations of spot samples for other scientific analyses. Photo credit Quentin Borderie.]

This project has been made possible due to its project partners and collaborations with several other research projects. The castle case studies represent a diverse range of cultural, environmental and heritage contexts across Europe, in which we could examine the preservation of stratigraphy, biological remains, artefacts and materials:

  • Elbląg, Poland, Karksi, Estonia, Cēsis, Latvia, important Teutonic Order castles in the Baltic region;
  • Castle Keverberg (Kessel), the Netherlands, which consisted of an original stone tower built in 1100 and covered by a motte-and-bailey castle;
  • Several French castles, which are Château de Caen, built in 1060, Château de Gien, which today hosts the National Museum of Hunting with the remains of an early (c. 9th – 11th AD) Carolingian castra below, Château de Loches and Château de Boves;
  • Two Italian case studies, Castelseprio, a UNESCO World Heritage site, and Montegrotto;
  • Molina de Aragón, Spain, situated in the Molina and Alto Tajo UNESCO Global Geopark;
  • Dunyvaig Castle, Islay, Scotland, formerly the naval fortress of the Lords of the Isles, the chiefs of the Clan MacDonald.

This project developed a framework for geoarchaeological research at European castles to target archaeologists, castle curators and heritage management policy-makers, so that our guidance can influence their future excavation strategies and conservation plans. Geoarchaeology applies environmental science techniques to archaeological research questions.  Soil micromorphology is a geoarchaeological technique that enables us to conduct a micro-excavation by analysing a slide, or ‘thin section’, produced from an intact, small block collected from the archaeological stratigraphy, so the inclusions are still in situ. The slide is analysed using a geological polarising microscope. Under the microscope, we record the same soil properties as archaeologists do in the field and additional ones, to understand the processes by which materials were deposited, how they have decayed due to chemical weathering, and how later human and faunal disturbances have affected the stratigraphy.

FIGURE 2. Micromorphology sampling of turf modifications to the curtain wall at Dunyvaig Castle, Islay, Scotland. Photo credit The Dunyvaig Project
FIGURE 3. Micromorphology sampling of occupation deposits sealed below later masonry and collapse during excavations ahead of conservation work on the eastern range of Cēsis Castle, Latvia. Photo credit Alex Brown
FIGURE 4. Micromorphology or ‘thin sections’ from  Elbląg (Poland) and Karksi (Estonia) castles. Photo credit Magnus Elandner

Soils and sediments are the backbone of the archaeological record. Our data revealed important stories within the soils about the early development of castle sites, the activities that took place inside different areas of the castle and how they may relate to the activities in a castle’s hinterland. We noticed that the preservation of the stratigraphy was exceptional owing to its burial under later masonry structures, masonry collapse and successive occupation layers; a phenomenon which is also observed on urban sites and Near Eastern tell sites.

Our results highlight the great potential and requirement for scientific analysis of these deposits when they are uncovered by excavation and/or building activities. These building activities include the conservation and renovation of the standing architecture and the removal of rubble, which can unseal buried archaeology affecting its preservation. Our analyses have revealed microscopic evidence for in situ animal husbandry and horse stabling, as well as the types of fodder that livestock were fed, crop processing activities, and periods of soil formation where areas of a castle have been abandoned or changed use. For example, at Castillo de Molina de Aragón, Spain, microstratigraphic data show the changing nature of the occupation the citadel, from the Islamic to Christian period which could possibly indicate a change in its role from a clean, well-maintained space to one where livestock roamed. The Islamic plaster floor surface was kept clean and very little domestic refuse accumulated  ̶  a soil formed over it, followed by a substantial destruction horizon. In comparison, units of discarded material and trampled floor surfaces characterise the (Re)Conquest phase, c. 1154, and a series of plaster floor surfaces with associated occupation residues containing herbivore dung showing that livestock were present, which probably relate to modifications during the thirteenth and fourteenth centuries.  

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Unravelling the past of Hoghton Tower

Steven Spencer and Elena Faraoni of the Hoghton Tower Preservation Trust, look at the results of their work, funded by the Castle Studies Trust in 2019, in trying to find out more about Hoghton Tower in Lancashire.

Hoghton Tower sits 650 ft above sea-level in the heart of the Lancashire countryside. The stories of its visitors and family members are documented and shared whether it be in books, portraits, family albums or documents in the Lancashire archives. But there is one story which has always intrigued us and that is: what was the first tower of Hoghton Tower and where was it? It is clear when looking at the building today that this, like many other historic houses, is a ‘patchwork’ of different projects by different generations interlaced and blended…but where did Hoghton Tower start? Where was the original tower?

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 There are some clues: the ageing of the stone, the position of the well house, family stories passed down the generations, the shape of the windows and a mysterious mound of stones on the north side of the buildings. One of these stones has an intriguing mason’s mark… Spurred on by the interest of a group of our amazing volunteers who had just finished some research into historic graffiti and masons’ marks it was time to do some investigation under the guidance of Dr Mike Nevell and his team at Salford University. We designed a research project based on archaeological digs, building recording, geophysics and archives research based on the key exam question “where was the great keep of the Hoghton Tower hill?”

North side of Hoghton Tower (copyright Hoghton Preservation Trust)

 Thanks to the grant from the Castle Studies Trust, work quickly got underway. Through a series of Salford-led workshops, the team surveyed, recorded and reviewed old photographs and pictures.

Then there was the wonderful five-day archaeological dig.

As they passed through the perimeter fencing on to the dig site, the usually mild-mannered volunteers underwent personality transformations as pairs of friends and even married couples were ‘pitted’ against one another. Was this the site of a 14th century Pele Tower, a 1643 victim of the First Civil War, who would make the crucial find?

Under the patient guidance and control of the Salford team, the test pits were marked out and the excavations began, to many this was the chance of a lifetime and was eagerly embraced. Each find was announced with enthusiastic shouting from the discoverer and muted derision from those yet to make a meaningful contribution.

Hoghton Tower Gatehouse from inside the courtyard (copyright Hoghton Tower Preservation Trust)

As the week progressed, 14th to 19th century finds were unearthed, thankfully shared out between the eight test pits. Clay pipe bowls (1640 to 1680), a musket ball, heat affected glass, sherds of medieval pottery and fragments of medieval roof tiles. Below a stone rubble layer, evidence of a stone-built structure was revealed in the form of large dressed stone blocks, together with walls and a stone flagged floor.

Spurred on by the whole experience, and encouraged by the de Hoghton family, the volunteers have produced and presented an ‘Outdoor History’ tour which aims to share the latest thoughts and discoveries. 

Was this the site of the Hoghton Tower? Did we find anything categorical? Well yes and no. The archaeology revealed previously unrecorded stone structures. These together with the artefactual evidence were able to confirm that this part of the hilltop was occupied during the late medieval/early post-medieval periods. The geophysics also gave us other areas that warrant more digging and researching. So, some confirmation but also a lot more to understand and discover on this windswept hill!

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Featured image of Hoghton Tower, copyright Hoghton Tower Preservation Trust

Geophysics and Castles: An Introduction

By Dr Kayt Armstrong, MCIfA

Hello! A personal introduction before we get down to the geophysics. I’m Kayt Armstrong, and I am an advisor to the Castle Studies Trust as a specialist in the use of geophysics in archaeology. I am also a member of the board of the International Society for Archaeological Prospection, and I represent the UK on a European research network about soils and geophysics in archaeology. I obtained my PhD in Archaeological Geophysics from Bournemouth University in 2010. I have worked in the UK and Europe (Greece and Italy) since that time, conducting archaeological geophysics in a variety of research and developer-led contexts. I help the CST evaluate funding applications that have geophysical elements, and also comment on the reports from any resulting work.

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What is ‘Geophysics’?

If you were a Time Team enthusiast, you probably already know the answer to this one!

Geophysics is the study of the physical properties of the earth (or other planets – you can do astrogeophysics!). It is an extensive term that encompasses whole planets, right down to understanding the microstructures of stone. Archaeological geophysics falls into ‘near-surface geophysics’, which studies the first 30m or so of the ground. In fact, commonly, archaeological geophysics is only really concerned with the top 2m or so; material in the topsoil, rather than the bedrock.

Geophysicists use a variety of methods and instruments to get information about the physical properties of the ground, such as its ability to conduct electricity, or its magnetic properties. Small variations in those properties can then be mapped. Buried archaeological material causes variations in the properties in predictable ways. This means we can map buried archaeology using these methods, without having to dig everything up.

When it comes to Castles, there are three main geophysical methods: earth resistance (‘resistivity’), magnetometry, and ground-penetrating radar (GPR). All three techniques look at slightly different aspects of the sub-surface, and all three have benefits and weaknesses. It is really best to combine methods to get as complete a picture as possible, as they will all tell you slightly different things.

Magnetometry

Magnetometry is probably the most commonly used technique in archaeology. It uses sensors to look at small variations in the strength of the earth’s magnetic field, to look for changes caused by buried material. The soil on sites where humans live becomes more magnetic over time, due to things like fires for cooking and warmth and the fermentation of waste material. This material becomes the fills of cut features like pits and ditches. These end up more magnetic than the soil they are cut into.

Structures used for processes involving heating, such as kilns, furnaces and ovens, become even more strongly magnetised and have a very characteristic appearance in the data. Similarly, fired ceramic building materials like brick or tile have a distinctive signal, as do igneous or metamorphic rocks (those modified by heating during their formation).

Magnetometry survey of Pembroke, funded by the CST in 2016

Magnetometry is very fast, covering upwards of 10ha a day if using the latest equipment. It is also relatively easy for community groups to employ. However, the pace will be somewhat slower using hand-carried single sensors. The plus-sides are the speed of survey and the wide variety of archaeological features that can be detected and mapped. The downsides are that this method is strongly disrupted by ferrous material in the survey environment, and has problems on igneous and metamorphic geologies as happened with the survey of Tibbers in 2014. It is also not very useful for mapping stone remains that are not strongly magnetic (such as some sandstones and most limestones). Modern infrastructure within or adjacent to the survey area has a far greater impact on the results than any buried archaeology (as happened in the Wressle survey of 2019), masking it from detection. It is practically not possible to use this method in urban areas. This method cannot detect smaller structures if they are buried more than about 2m below the ground surface. Features in the first 2m can usually be detected but the size of the anomalies that can be distinguished depends on the resolution of the readings taken. However, this method doesn’t let you understand the depths of the anomalies, and so isn’t as helpful on multi-period sites.

Earth Resistance

Earth resistance examines how easy it is to pass an electrical current through the ground. The resistivity of the subsurface varies in relation to several properties. Still, the most substantial effect is caused by variations in moisture content. The fills of cut features like pits and ditches (as witnessed in the 2018 survey at Laughton which showed a possible ditch, confirmed in the 2019 excavation and of Tibbers which lead to the discovery of a new inner bailey) tend to have a more open texture than natural soil. They usually also contain more organic matter. This means they are generally wetter than the ground they are dug into. Conversely, buried structures like walls and floors, are usually much drier than the material surrounding them, because they can’t absorb as much water.

Earth Resistence Survey at Tibbers, co-funded funded by the CST in 2016. Copyright HES

This technique can be applied in two ways. You can collect a grid of readings over a flat area to examine the first 2m or so, producing a plan view. You can also collect long lines of readings with increasingly wide measurement points. This is called ‘Electrical Resistance Tomography’ or ERT, and produces vertical pseudo-sections through the ground, and can reach greater depths, typically in archaeology 8-10m.

The plan-view method typically involves 2 probes on a mobile frame, and two remote probes connected by a cable. 2 of the probes inject a current, and two measure the resistance to it. It is especially useful for mapping buried stone structures. It is therefore handy on ‘Castle’ sites where multiple building phases can be expected. It is relatively slow, however, and relies on being able to insert probes into the ground to get the readings. This is fine on a lawn or field, and it can work on paths and gravel, but the results get very noisy, and it isn’t possible over flagstones or tarmac or concrete. You also need to be able to manoeuvre the cables and place the remote probes at an appropriate distance. This method also doesn’t let you understand the relative depths of various anomalies.

ERT is less commonly used in archaeology, but it has some specific applications in the study of large defended sites. Because it can resolve structures at a greater depth than the plan-mode, it can be used to examine the construction of large structures. This includes moats, earthen banks and buried fortification walls, and other such features. If multiple adjacent profiles are collected, the data can be combined into a 3D model of the subsurface, which can help resolve questions about the construction sequence of a site.

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Twin-probe (plan-view) resistivity survey is relatively straightforward to carry out. It doesn’t require as much skill on behalf of the instrument operator as magnetometry does. It is however, slow and laborious. The equipment is relatively cheap, and data processing and visualisation are relatively simple. This method is rarely used in the commercial sector these days but is an ideal research tool. Community groups have produced excellent research using this technique. The ERT method requires specialised equipment and a trained collector. The background knowledge needed to correctly process and interpret the data is also high.

Ground Penetrating Radar

GPR only made the odd appearance on Time Team, but in the last decade or so advances in computing (mostly increasing miniaturisation of components, and improvements in battery life) have led to a new generation of GPR kit that is more flexible and affordable.

GPR works a lot like sonar or the sort of radar employed by aircraft. A transmitting antenna sends out radio waves focused into the ground. These propagate downwards and are reflected by abrupt changes in the material of the subsurface. For example, when the waves leave a stone ceiling and move into the vault, some of the waves will be reflected back up. Some will continue on, to encounter the floor of the vault, and anything below it. The reflected waves are collected by a receiving antenna (usually in the same ‘box’ as the transmitter, a fixed distance apart). The strength of the returned waves, along with the time (in nanoseconds!) it takes for them to return is logged and plotted. This is a single trace.

Ground Penetrating Radar Survey at Shrewsbury Castle 2019, funded by the CST

The antenna is dragged along a line, and a series of traces are collected at a small interval (usually every 5cm or 2cm), which are combined together to make a profile. This is effectively a vertical slice through the ground. These are a bit difficult to read because the radio waves emit in a curved shape, so they actually travel in front of and behind the antenna, not just directly under it. This creates distinctive hyperbolas in the data. The depth of signal penetration and the size of the objects you can detect varies with antenna frequency. Depending on the frequency of the antenna, you can look very shallowly and resolve things that are a centimetre (or less) across. Very high-frequency antennas are used to assess the structure of concrete in civil engineering or to image different layers in mosaics and floor coverings. Lower frequency antennas cannot resolve smaller anomalies but can penetrate 10m+ to resolve much larger objects, such as former river beds, large walls or banks and ditches.

Groups of profiles collected in parallel lines can be combined together to make a 3D block of data. This can be processed in a way that allows different horizontal depth slices to be examined (as done at Fotheringhays; see time slice). A new generation of GPR system uses lots of antennas in an array to collect very high- resolution datasets (8cm in all directions), or arrays of different frequencies to quickly collect data with good resolution at multiple depths.

GPR requires a skilled operator to plan the work, collect the data and the process and analyse the results, but it is arguably the best technique for investigating Castle sites. This is because it tends to be good at detecting the sorts of things we would expect to be looking for, for example, voids, buried walls, culverts and surfaces. It can also be deployed inside standing buildings, to look underneath floors or behind walls. It can be used over tarmac and concrete (providing the concrete is not re-inforced!) and does well on most geologies, except for certain kinds of clays, and saline environments like estuaries.

The other advantage of GPR is that the data is relatively fast to collect, compared to earth resistance, and a broader range of features can be detected with it. It is also an inherently 3D method and allows complicated below-ground sequences to be visualised and interpreted. I have seen examples of staircases being visible in the data from 3D GPR, for instance. This technique has made the headlines recently, with the publication of a study of an entire Roman city, Falerii Novi, just north of Rome, by colleagues of mine from Ghent University and Cambridge University.

Geophysics and the Castle Studies Trust

Geophysical approaches form an increasing component of research proposals put to the trust, which is excellent to see! Geophysics can help to answer both broad and specific questions about castle-sites, without the potentially destructive process of excavation. Geophysics also has applications for the conservation of sites and planning for their future management. For example, in mapping the integrity of standing walls using GPR, or understanding the soils and material within earthworks to protect them from erosion in extreme weather events. They can help site managers decide whether an intervention is necessary, and can inform the design of any needed work. Geophysics can also play an essential role in the continuing life of these sites as homes or places of historical interest by mapping areas where conservation or building work is planned to ensure nothing is damaged by the work.

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Featured image is of the earth resistance survey at Pembroke in 2016

Castle Studies Trust Christmas Quiz – the Answers

So how many did you get right? Find out below

  1. Lincoln (2020 project)
  2. Pembroke (2018)
  3. Shrewsbury (2018 and 2019)
  4. Pulverbatch, Shropshire (2017)
  5. Pleshey, Essex (2015)
  6. Druminnor, Aberdeenshire (2019)
  7. Thornbury
  8. Warkworth (2020)
  9. Ruthin
  10. Ravenscraig, Aberdeenshire
  11. Hoghton Tower, Lancashire (2019)
  12. Wigmore
  13. The Wirk (2020)
  14. Slingsby, Yorkshire – article by Bethany Watrous on her digital reconstruction
  15. Caus, Shrophshire (2016)
  16. Gleaston, Cumbria (2015)
  17. Laughton (2018, 2019)
  18. Shrewsbury again (found during 2018 execavation)
  19. Clifford, Herefordshire (2017)
  20. Ballintober, Ireland (2014)

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Castle Studies Trust Christmas Quiz

To help keep you entertained during this strange and hopefully unique Christmas the Castle Studies Trust has prepared a Christmas quiz. Can you name the castles these pictures are or images are taken from either our projects from all years or blog posts during the year?

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  1. Where is this?

2. Where did this CST funded excavation take place?

3. Where is this?

4.What motte and bailey castle, which we funded a geophysical survey for, is this?

5. Where can you find this bridge which the Trust co-funded post excavation work on?

6. In which Scottish castle did the geophysical survey we funded find this well?

A latter coming protruding from a circular opening in the ground.
Photo by Iain Ralston and licensed under a Creative Commons Attribution ShareAlike 4.0 licence.

7. Where is this?

8. Where is this great tower?

9. This is a reconstruction drawing of which castle?

10. Where is this castle built by a queen?

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11. Where is this castle?

12. The entrance to which border castle is this?

13. Where is this base a tower? It’s one of the projects the CST has funded

14. Where is this?

15. The plan of which castle is this, which the CST funded work on?

16) Which castle is this? We funded a building survey on it previously?

17. For which castle are these aerial images of, which include results of the geophys survey the CST funded on it?

18. These pieces of Saxon pottery were found at which excavation the CST funded?

19. This is a CST study day at our first ever excavation we funded? Which castle?

20. The CST funded a buildings survey of this castle. Where is it?

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James of St George and the Edwardian Castle

Malcolm Hislop, researcher and author, writes about some of the themes of his most recent book.

Often thought as a highpoint of English military architecture, the castles of Edward I and his followers in north Wales hold a special place in hearts and minds of many in this country and abroad. Scholars have spent much time and effort on researching this (relatively brief) episode of intensive castle construction. We feel we know these buildings so well, and yet, notwithstanding the many accounts of individual castles, it is strange to relate that no lengthy general survey of the architecture (as opposed to the building history) has ever been published. Nor, despite presenting an obvious opportunity for furthering our understanding of the manner in which architectural style was formulated and disseminated in the late thirteenth century, have the influences on and of the Edwardian castle been widely discussed.

Conwy. The outer gatehouse and truncated approach ramp of c. 1283 by James of St George.

Edward’s Welsh castles are inextricably linked to the technical mastermind behind the project, the Savoyard mason, James of St George. Castle builders (in the practical sense) tend to be less well known than their patrons. The ones who can be identified are far outweighed by those who remain anonymous. Moreover, a master builder whose career can be reliably reconstructed to a significant degree is a rarity to be cherished. Master James is one such exception, his reputation as an architect of international repute being established in one of the great historical detective stories of the later twentieth century, which did much to personalise the often anonymous process of medieval construction.

Beaumaris. The North Inner Gate of c. 1295 etc. by James of St George.

Master James’ star has not ridden quite so high in recent years. His architectural role questioned, his artistic contribution doubted, James now seems a slightly diminished figure, with only his organisational and planning abilities remaining unchallenged. There were certainly other master builders employed on the royal works who exercised a degree of independence; it is clear too that there were other influences on the royal works in Wales than can be accounted for by Master James’ accumulated experience in Savoy. In particular, what was the part played by Walter of Hereford, the technical and artistic master mind behind Vale Royal Abbey, and resident master at Caernarfon from 1295? These are interesting issues requiring a greater depth of enquiry, but the initial conclusions of a broader than usual sweep of the architecture are that in addition to his organisational and technical responsibilities Master James also exercised a significant creative role.

Duffus. The great tower of c. 1305 built in Moray with Edward’s assistance.

Edward’s crushing of all resistance in north Wales was swiftly followed by an attempt to subjugate Scotland. Building work in Wales was mothballed and James of St George and Walter of Hereford were redirected northwards. The impact of Edward’s invasion of Scotland on castle building in the northern kingdom tends to receive little attention. Most of the royal works were in timber, little survives above ground level, and archaeology has not yet revealed much that can enlighten the subject. On the other hand, it is becoming increasingly clear that there is a good deal more to say about the contemporary building works of his supporters, that survival of which is much greater, and that in a number of instances there was an English contribution to design and construction. The story of Edwardian castle building in Scotland is only just beginning to take shape.

Newark. The river front of c. 1300, probably influenced by Caernarfon.

Another under-researched theme is the effect of the Edwardian castles in Wales on the architecture of England. There has been an understandable tendency to view the years immediately following the Edwardian conquest of Gwynedd as an anti-climax in English castle building, and that there is little continuity from the Welsh project. Yet the craftsmen dispersed, and building went on, not in such concentrated or dramatic fashion, but often in small quiet ways that escape the notice of the wider world. The full extent of this influence on fourteenth-century castle design is yet to be recognised, but it includes both the broader aspects and the smaller details and represents the final chapter in the story of the Edwardian castle.

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Malcolm Hislop’s book James of St George and the Castles of the Welsh Wars (September 2020) is published by Pen and Sword. Hardback, 302 pages, 175 colour and monochrome illustrations.

A Large and Eclectic Crop of Fascinating Applications for the Castle Studies Trust to Consider

The deadline for grant applications passed on 1 December. We’re going through the various projects now. Altogether the 14 projects, coming from all parts of Britain, one from Ireland, are asking for £88,000. They cover not only a wide period of history but also a wide range of topics.

We will not be able to fund as many of these projects as we would like. To help us fund as many of these projects as possible please donate here: https://donate.kindlink.com/castle-studies-trust/2245

In a little more detail here are the applications we’ve received:

Caerlaverock, Dumfriesshire: The aim is to understand the chronology and geography of extreme weather events in the high medieval period, and the effects they wrought on archaeological features that led to the abandonment of the old castle in favour of the new.

Georgian Castles: This project explores two castles in County Durham—Brancepeth and Raby—that were fundamentally reshaped and transformed in the eighteenth century to become notable homes in the area, and it advances not only our understanding of these two buildings in the period, but also the afterlife the castles in the area and the layers of history that they record.

Greasley, Nottinghamshire: The production of an interpretative phased floor plan for Greasley Castle in Nottinghamshire. The castle, built in the 1340s, has an obscure history and the understanding of its architectural phasing is at best very cloudy.

Laughton-en-le-Morthen, South Yorkshire: To provide professional illustration and reconstruction which will also be integrated into the co-authored academic article. Part of the monies will be used to produce phase plans of Laughton during key stages of its development, and a small percentage will pay for a line drawing of the grave cover.

Lost medieval landscapes, Ireland: To develop a low cost method, using drone and geophysical survey to identify native Irish (also termed Gaelic Irish) medieval landscapes and deserted settlements.

Mold, Flintshire, post excavation analysis: Post-excavation analysis from excavation on Bailey Hill of the castle

Mold, Flintshire, digital reconstruction: Visual CGI reconstruction of  Mold Castle using the new-found evidence of further masonry on the inner bailey structure and using information gathered by the Bailey Hill Research Volunteers, showcasing the many changes that have happened on this site from a Motte and Bailey Castle to present time as a public park.

Old Wick, Caithness: Dendrochronological assessment of timber at the Castle of Old Wick, Caithness thought to be one of the earliest stone castles in Scotland.

Orford, Suffolk: recording the graffiti at the castle through a detailed photographic and RTI (Reflectance Transformation Imaging) survey will add to our understanding of how the building was constructed and the ways the building was used over time, particularly 1336-1805, during which the documentary history of the castle provides little evidence of how the site developed.

Pembroke, Pembrokeshire: A second season of trial-trench evaluation of the suggested late-medieval, double-winged hall-house in the outer ward at Pembroke Castle, which is of national significance. The evaluation builds on the results of the works undertaken through previous CST grants: geophysical survey (2016) and 2018 whereby two trenches were excavated across the possible mansion site. The evaluation will again establish the extent of stratified archaeological deposits that remain within the building, which was excavated during the 1930s.

Pevensey, East Sussex: GPR survey of the outer bailey and immediate extramural area and UAV (aerial) survey of the castle to build up a 3-D model of the site.

Richmond, North Yorkshire: Co-funding a 3 week excavation of Richmond Castle, one of the best preserved and least understood Norman castles in the UK. The aim is to understand better the remains of building and structures along the western side of the bailey.

Shootinglee Bastle, Peeblesshire: Funding post-excavation work from the 2019-20 excavation season in particular some charcoal deposits from a C16 burning event.

Warkworth, Northumberland: Geophysical survey to explore evidence for subsurface features in and around the field called St John’s Close in a field adjacent to the castle.

We will not be able to fund as many of these projects as we would like. To help us fund as many of these projects as possible please donate here: https://donate.kindlink.com/castle-studies-trust/2245

The applications have been sent to our assessors who will go over them and prepare their feedback for the Trustee’s who will meet in late January to decide on which grants to award.

Geophysical survey at The Wirk reveals buried walls of the hall

Project leads, Drs Sarah Jane Gibbon and Dan Lee reveal the results of the geophysical survey part of their project on The Wirk funded by the Castle Studies Trust.

Thanks to a grant from the Castle Studies Trust, ateam from the Orkney Research Centre for Archaeology undertook geophysical survey at The Wirk, Westside, on the island of Rousay, Orkney in September, despite the challenges. Long grass was cleared from the site and a grid was established to the north, east and west of the stone-built tower. Two techniques were used: magnetometer survey (good for identifying magnetically enhanced material from burning and settlement activity) and earth resistance (good for locating walls and structures).

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The aim is to better understand the nature and date of the tower which has variously been interpreted as a 12th century Norse Castle, a hall-house tower, a defensive church tower and a 16th century tower and range. Previous excavations by J. Storer Clouston in the 1920s cleared the stone tower and exposed a large range to the east, although phasing of the buildings remains unclear. The tower was left exposed but the area to the east was backfilled. A scale plan was made but recording and description of the built remains was minimal.

High-resolution magnetometer survey and targeted high-resolution earth resistance survey was undertaken across the site in order to characterise the buried structures, put the tower and hall in context and inform trench location. Clear anomalies were identified in both surveys at the site of the hall, with potential wall lines (high resistance) matching the main part of the building in Clouston’s plan to the east of the tower. This suggests that wall footings are likely to survive just below the ground surface. Other high resistance anomalies to the south of the hall could indicate the presence of additional structures. Results from the magnetometer survey showed strong positive and negative anomalies within the footprint of the hall and confirmed the presence of a possible enclosure to the south. A curvilinear positive anomaly to the north-west of the tower, beyond the apron, could indicate the presence of another small enclosure.

Overall, the geophysical survey has demonstrated that the footings of the hall survive to the east of the tower, accompanied by newly discovered enclosures with possible structural elements to the south and north-west. The extent of the site appears to extend beyond the visible remains with anomalies continuing into the kirkyard.

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Featured image copyright of Bobby Friel @TakeTheHighView

ORCA have had to postpone the evaluation excavation until next year, but the prospects are looking good to expose some of the hall.

A wooden castle scratched in stone: a 13th-century graffito from the castle at Caen

Dr Edward Impey, one of the UK’s leading castle experts and patron of the CST examines some C13 graffito can boost our understanding of castles.

As every castle book reminds us, the defences of most castles before the mid-13th century, and the buildings within them, were built of earth and timber. The perishable nature at least of the timber parts, and their replacement in many cases in stone (obviously) makes their structural detail hard to understand, although Robert  Higham and Philip Barker’s Timber Castles of 1992, and their publication of Hen Domen (Montgomery) in 2000 achieve a great deal in this direction. As most evidence is archaeological, however, it tends to be confined to plans and layout. Herein lies the importance of this graffito, scratched into a re-used ashlar in the early 13th century and found during the excavation of the long-demolished donjon in the castle at Caen in 1966: it shows, in elevation, what is unquestionably a timber-framed castle, or part of one – either a ringwork or a motte.


The graffito re-drawn, omitting the underlying mason’s tooling and lines probably unconnected with the original image.

To begin our description with the mound on which the buildings stand, this is marked with a series of lines inclining inwards towards the top, which may be the draughtsman’s device to give it substance, or, possibly, represent baulks of timber covering the slope – a variant of the arrangement found for example at South Mimms (Hertfordshire) and elsewhere. To the extreme right, similarly striated, is what must be the counterscarp of the ditch, and springing from it, possibly propped by two trestle-like structures, is the bridge across it: this is of the so-called ‘flying form’ shown in the Bayeux Tapestry and found archaeologically at Hen Domen. At its top end the bridge abuts a tower, necessarily a gate tower, its side scored with the diagonal intersecting lines, probably representing cross-bracing of the form found in the bell towers at St Leonard’s, Yarpole (1195-6) and St Mary’s, Pembridge, of 1207-23 (both Herefordshire); variants are known in France and over forty post-medieval examples in central Europe. The arrangement is also shown in a carving at Modena cathedral, and in numerous 12th -and 13th– century bestiary illuminations of timber towers on the backs of elephants, prompted either by Pliny the Elder’s or the Books of the Maccabees. Siege towers could be similarly constructed, hence the French term beffroi.

. The re-drawing numbered to indicate the main features described in the text.
1. Revetted earthwork slope
2.The moat counter-scarp
3.Bridge
4.Possible trestles supporting bridge
5.Gate tower
6.Oversailing platform at tower top
7.Timber wall
8.Possible second tower
9.Battlement
10.Hoist
11.Hall?
12.Second building within the enclosure
Third building

Abutting the tower is the battlemented wall or palisade, composed of edge-to-edge vertical timbers, reinforced by a horizontal rail at top and bottom and by massive diagonal or ‘X’ braces, face-nailed to the uprights.

Inside the enclosure, our draughtsman has shown at least three buildings. The most prominent has a pitched roof terminating in finials, with a row of four round-headed windows under the eaves. Conceivably this was intended as a chapel, but the windows more probably belong to the clerestory of an aisled hall, as survive in the single-aisled hall of c.1160 in the castle at Creully, seventeen kilometres north of Caen, and has been inferred in the 12th-century timber examples at Leicester castle and the Bishop’s Palace at Hereford. In front are two lower buildings with pitched roofs, one carrying a finial.

To the left of the hall is a structure consisting of a vertical pole, a cross-bar at the top, propped by diagonal braces. At first sight rather puzzling, this is clearly identifiable as a crane or hoist, thanks to the dozens of near-identical examples in medieval images, conveniently gathered together by Günther Binding’s compendium of 2001. To the right  of the pole hangs a  rope, taut  as if being pulled or winched downwards, and which is carried over the cross-bar and two faintly-indicated pulley wheels, beyond which it hangs down again and appears to be in the act of hauling a large timber into the air.

The value of the depiction can be summarised as follows. First, it may be the only contemporary representation of a timber-built motte-top or ringwork complex, and is valuable in showing the whole apparatus of palisade, battlements, bridge, gate tower and buildings within. Second, along with the Abbaye aux Dames capital, it is one of only two known representations of face-nailed ‘X’ bracing – an arrangement by definition untraceable archaeologically – which would have endowed the palisade with immense lateral strength and was perhaps widely used. Third, this may be the only contemporary representation of a Romanesque aisled hall – if that is what it is – within a castle. Fourth, as the battlemented platform at the top of the tower oversails its sides, forming a machicolation, it is one a number of images showing that such things did not derive from hourds, but were integral at least to timber towers long before appearing in stone. Fifth, while it has long been assumed that medieval defensive towers in timber were structurally akin to 12th- and 13th-century bell-towers, this is, apart from the Modena carving, the only one to actually show this to be so. Finally, although representing a well-known type, the crane certainly adds liveliness and interest to the composition.

Who the draughtsman was is, obviously, unknown. So is whether the graffito represents a real or imaginary place, although the inclusion of the crane, in use, could be taken as a hint that a particular site, where building works were under way, was indeed intended. What is clear is that it is not a picture of the castle at Caen, nor indeed of Creully, both of quite different form.

Let’s hope that this blog and the forthcoming article (in French) will encourage the identification of other wooden castles scratched in stone, and help with their interpretation and of excavated evidence in the future.

Featured image: The graffito (reproduced by kind permission of the Musée de Normandie, Caen)

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To find out more about the working being done at Caen you can visit her: https://caen.fr/actualite/un-parc-paysager-la-conquete-du-chateau

Bibliography

M. Baylé,  La Trinité de Caen: sa place dans l’histoire de l’Architecture et du plate et du Décor Romans (Paris, 1979),

A.R. Boucher and R.K. Morriss, ‘The Bell Tower of St Mary’s Church, Pembridge, Herefordshire’, Vernacular Architecture, vol. 42, issue 1, pp.23-35

G. Binding, ed., Der Mittelalterliche Baubetrieb in zeitgenössischen Abbildungen, (Darmstadt, 2001), available in translation as Medieval building techniques, (Stroud, 2004).

M. De Boüard, Le Château de Caen (Caen, 1979)

R. Higham and P. Barker, Timber Castles (London,1992)

R.Higham and P.Barker, Hen Domen, Montgomery – A Timber Castle on the English Welsh Border (Exeter, 2000),

Karel Kuča & Jiří Langer, Dřevěné kostely a zvonice v Evropě (Timber Churches and Bell Towers in Europe), 2 vols.(Prague 2009)

N. Molyneux, ‘The detached bell tower, St Leonard’s Parish Church, Yarpole, Herefordshire, Vernacular Architecture, vol. 34 (2003), issue 1, pp.68-72