Is The Wirk a Castle? Archaeological investigations in Rousay, Orkney

Dr Sarah Jane Gibbon and Dan Lee (UHI Archaeology Institute / ORCA) project leads for the Castle Studies Trust funded project explain the reasons behind the excavations they are undertaking at The Wirk in the Orkneys and what they hope to achieve during their two week dig.

Located on the south-western coast of Rousay, The Wirk is located in one of the most archaeologically rich parts of Orkney. The Orkney Research Centre for Archaeology (ORCA) is undertaking geophysical survey, archaeological excavations and 3D modelling at this enigmatic castle site (pending approval from HES).

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The Wirk, meaning stronghold in Old Norse, and with the alternative name Westness Castle, is a small stone tower located close to the coast. It has variously been interpreted as a 12th century Norse Castle, a detached fortified bell-tower, a 13th century defensive tower for an incomplete church, a hall-house garderobe tower and most recently a 16th century tower and attached range.

View of The Wirk, located on the righthand corner of St Mary’s Church yard in the foreground, looking northwest to Midhowe and the Atlantic Ocean (Image: Bobby Friel @TakeTheHighView).DCIM100MEDIADJI_0558.JPG

Minor clearance and excavation in the 1920s identified similarities in construction between The Wirk and the 12th century Cubbie Roo’s Castle, on the nearby island of Wyre, considered to be one of the earliest stone keeps in Scotland. The Wirk is located in Westness which has been a large estate since at least the 12th century when it was the home of the Norse chieftain Sigurd of Westness (Orkneyinga saga). It is adjacent to Rousay parish church, likely to date from the 12th century, with standing remains of 16th century date on earlier footings.

Recently, the 12th/13th century date attribution of The Wirk has been rejected in favour of a 16th century date. This new interpretation is based on the built remains and 16th century architectural fragments which were found in the 1920s. However, architectural fragments of 12th/13th century date were also present and nearby archaeology, particularly the discovery earlier this year of a Norse hall at Skaill by the UHI Archaeology Institute would suggest this was a high-status place in the saga period. This is not to dispute that The Wirk may also have been in use in the 16th century when the estate was owned by a prominent Orkney family. One of the objectives of this project is to excavate trial trenches over Clouston’s excavation and at the eastern end of the site to identify the earliest phases of the tower and adjacent building. Upper parts of the tower were substantially rebuilt in the 19th century and so excavation will allow us to record parts of the site that have not been knowingly rebuilt.

Inside The Wirk tower, looking southeast, showing the entrance to an underground well or passage (Image: Dan Lee)

Along with the excavations, targeted geophysical survey around The Wirk undertaken in September 2020 aims to better understand any relationships between the tower and the buildings/features which surround it. The results show that the walls planned by Clouston are accurate and that they likely survive just below the ground surface. 3D modelling of The Wirk and Cubbie Roo’s Castle will enhance our understanding of these comparable sites and allow the public to explore the remains online.

 The start of the project was delayed in 2020 due to the Covid-19 pandemic, and we will be glad to finally get on site for the excavations in July.

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References and further reading:

Clouston, JS 1931 Early Norse Castles. The Orcadian. Kirkwall

The Virtual 3-D Reconstruction of 12th-Century Lincoln Castle

Dr Jonathan Clark, Historic Buildings Director, FAS Heritage and project lead for the Castle Studies Trust funded 3-D Reconstruction of C12 Lincoln Castle explains how it was done and the challenges faced in doing it.

A virtual 3-D reconstruction of Lincoln Castle as it may have looked in the late 12th-century has been completed by Peter Lorimer, Pighill Illustration in collaboration with FAS Heritage.  The reconstruction was funded by the Castle Studies Trust and made possible through 15 years of archaeological research for the Lincoln Castle Revealed project. The project consisted of a £22m repair and restoration programme to conserve the site and renew the visitor experience funded by the National Lottery Heritage Fund, Lincolnshire County Council and the European Regional Development Fund. The programme provided opportunities for research-led archaeology which yielded a wealth of new information about the site.

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Mondern day Lincoln Castle from the west copyright Andy Tyner Photography on behalf of FAS Heritage and Lincolnshire County Council
Lincoln Castle as it could have been in the late C12 copyright FAS Heritage and Pighill Illustrations

William the Conqueror established Lincoln Castle in 1068 in the walled enclosure of the former Roman colonia. The Lucy Tower motte was built in its southwest corner reusing the west and south walls to defend the new inner bailey. The next 100 years saw rapid development: originally earth and timber, the Conquest-period castle was replaced in masonry, a process now understood to have started by the 1080s including East and West Gates; by the early 12th century the stone enclosure of the bailey and internal gate ranges were complete, along with the Lucy Tower shell-keep and later Observatory Tower. Inner bailey buildings were also contacted during excavation including the Great Hall, stables, East Range and the Observatory Tower motte and ditch, all contributing information to the reconstruction. Evidence for a lost South Gate to match East and West Gates was found; along with a reappraisal of the early form of the Lucy Tower shell-keep it provided information about a former southern enclosure. This enclosure was abandoned, probably by the early 13th century, when the castle contracted to the form of the current enclosure.

It was the culmination of this intense century of development, arrived at by the late 12th century that was selected for the digital reconstruction.

Plan of Lincoln Castle in C12 copyright FAS Heritage

Archaeological excavation and detailed building recording formed most information about the early form of the castle, but the assembly of the 3-D reconstruction led to reappraisal of other parts of the castle; previously unnoticed anomalies were discovered which required further analysis.

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The lost southern enclosure and South Gate were both identified from fragmentary evidence and establishing the exact position and size of the original south wall presented a challenge. When reconstruction began there was little information on this wall except a projection of the line of the southern colonia wall. This placed the south wall slicing through the Lucy Tower motte – a relationship which did not seem likely. However, recent work on this part of the motte during a programme of banks stabilisation provided more information. A substantial medieval masonry wall measuring 3m wide and traversing the Lucy Tower motte west-east was revealed. The wall is probably founded on the Roman wall indicates the motte may have been constructed against it, flattening its southern side.

The Lucy Tower Motte after the removal of dense vegetation.  The fragmentary masonry remains of a structure can be seen towards the top of the trench. Copyright FAS Heritage

The reconstruction provides a sense of where concentrations of occupation were; around East Gate and Observatory Tower, the Lucy Tower, the Great Hall and around West Gate. With the discovery of South Gate it is easier to appreciate how these areas were autonomous. Other areas within the castle, particularly the western side, are presented as large open spaces; without further investigation these zones cannot be reconstructed easily.

The Lucy Tower, sat upon on an enlarged motte, can now be shown with its original east and west chamber blocks, internal ranges and window overlooking the city. With the tower, wing walls and South Gate, these formed a discrete enclosure.

Detail on the form of the Observatory Tower in the late 12th century can also be added. The tower is shown as a gaol tower which replaced a predecessor developed by Earl Ranulf during the Anarchy, later commandeered to become the county gaol. A stone ‘skirt’ around the base of the motte and a motte ditch were found and formed a hard circuit detaching the gaol from the rest of the castle.

The reconstruction will be made available across a range of media. The analytical process and collaboration with Pighill Illustration provided an opportunity to translate the archaeological study of the castle into a tangible representation. It enables the results of the research programme to be conveyed to a wide audience and goes hand-in-hand with the publication of a book about the Lincoln Castle Revealed Project in July 2021.

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Taking Care of Herself. Duchess Richardis of Schleswig and the siege of Sønderborg castle (1358)

Dr Stefan Magnussen of the University of Leipzig looks at the extraodinary case of Duchess Richardis of Schleswig who in the C14 protected her rights over a castle at the expense of her husband’s.

In south-western Denmark, not far from the mouth of the Flensburg Fjord, rises a red-brick castle called Sønderborg (Eng: Southern Castle). Although it is hardly known beyond Denmark, at least its name still radiates throughout Europe as the eponym of the dynasty that originated from it. We do not know today who built the castle, which was first mentioned in 1253, but the eventful history as a residence, in which many men have left an architectural imprint, is well documented.

Aerial photo of Sønderborg Slot (unknown photographer, 1994), © Museum Sønderjylland]

Yet there were also some women who left their marks – this is especally true for Queen Dowager Dorothea of Saxe-Lauenburg, who commissioned the magnificent palace chapel. One key figure, however, has more or less fallen into oblivion: Duchess Richardis of Schleswig, who played a brief, but prominent role during a royal siege of 1358. Not so much as a leader of defence, but rather as a ruler who self-confidently defended her own interests – even if it meant turning against her spouse.

Drawing of Sønderborg Slot in its supposed structural state prior to the massive reconstructions of 16th Century. Drawing by former Head of the Museum Sønderborg, Jens Raben (1880-1960), © Museum Sønderjylland

Overall, very little is known about this woman. She was born around 1320 as the daughter of the Counts of Schwerin-Wittenburg and probably married Duke Valdemar V of Schleswig around 1338, presumably in the course of alliance negotiations. As was customary in those years, she was probably assigned the ducal secondary residence of Sønderborg with the island of Alsen as life tenancy, which made her Lady of Sønderborg for almost half a century until her death around 1386. Nevertheless, apart from the fact that her chaplain came from her native Wittenburg, little is known about her regency. Even her burial place remains a secret.

The preserved Seals of Richardis of Schleswig, indicating her heritage from the Counts of Schwerin-Wittenburg. Source: Thiset, Danmarks Kongelige Sigiller, Tab. 42

And yet what makes this enigmatic princess interesting is her key role in her husband‘s conflict with King Valdemar IV of Denmark. Understanding this and her stuation, it is worth telling the story from the beginning: In 1340, King Valdemar IV inherited a difficult legacy, as his realm was almost entirely pledged to various neighbours. Before homage was paid, a series of treaties reorganised these pledges, transferring almost all of Jutland to Duke Valdemar V, who in turn mortgaged his territories to the Counts of Holstein, who were among the leading negotiators. Within a few years, the Danish king succeeded in almost completely redeeming his realm, with the exception of some districts like Ribe Castle on the North Sea, which was still in ducal possession. At the same time, the Duke also succeeded in redeeming two thirds of his duchy from the Counts, who, however, remained  holding  the ducal principal residence at Gottorp. Since the secondary residence of Sønderborg had also been ceded to the Duchess, the castle district of Ribe constituted the last ducal power base. Notwithstanding this, King Valdemar IV. pressed for this pledge to be dissolved in 1351, which severely curtailed the Duke‘s power. In turn, the duke allied himself with the loyal Jutish nobility and the Counts of Holstein against the Danish king. An early conflict was settled in 1353, but flared up again in 1358.

Map of medieval Denmark with the island of Alsen and the castles mentioned in the article, by Stefan Magnussen

King Valdemar IV now ventured an advance on the island of Alsen, which lay just off the coast of the duchy in the direction of the kingdom. Within three days he was able to bring Nordborg Castle (Eng: North Castle) under his control, making the conquest of Sønderborg only a matter of time. But it was not the Duke awaiting him there, but Duchess Richardis. The main source for the recreation of the processes now taking place is the contemporary and royalist Younger Zealand Chronicle, which, albeit otherwise only reporting sieges in short, recounts the meeting in surprisingly colourful words. Richardis, together with „her girls“, which probably referred to her dames, had approached the King outside her castle. As she was a fine, clever and, morever, eloquent person, the Danish king immediately recognised her noble personality and decided that his friendship with her brother was more dear to him than enmity with the Duke. Both sides thus agreed that Richardis would be allowed to keep her estate undiminished in return for her promise that no harm would derive from it. That these events actually occurred is witnesses by a preserved charter, which also informs us of another juicy detail: Richardis also banned her husband from staying in his castle. It was only on two days a year that he was allowed to stay there.

Seals attached to the Charter from June 19, 1358, source: Dansk Nationalarkivet, Ny Kronologisk Række (1980–1981), Nr. 832-c.

So, how can we explain these events and, above all, this dazzling account? Apparently, in the face of the siege, Richardis proved to be a princess with a sense of rank who knew how to protect her sphere of power. With Duke Valdemar V having only a small remaining territory and little income since the loss of his most important castle of Ribe, Richardis had little to rely on from her politically incapacitated husband. Yet, Richardis probably anticipated the royal dilemma, for her brother was one of the king‘s key allies. The duchess and the Danish king thus agreed on a mutually beneficial solution that would potentially establish a royal bridgehead at the doorstep of the Duchy. This agreement, however, had a crucial pitfall in that the castle de iure belonged to the Duke, which legally limited the authority of the Duchess to freely dispose of it. But both sides sought to actively influence the interpretative authority of this conflict between norm and practice via the contract as well as the chronicle. This is indicated by the comparatively extensive set of 21 seals, which may have been intended to symbolise broad support by local elites, but also by the very favourable account of Richardis, which was probably intended to strengthen her personal authority and thus bestow legitimacy on the agreement. Both seem to have succeeded in this endeavour, for in the winter of 1372/73 Valdemar IV was able to use Sønderborg castle as his bridgehead during his advance on the city of Flensburg, and Duke Valdemar V is never again witnessed on Sønderborg Castle until his death in 1364.

Even though Richardis has been forgotten down the years, her brief, but crucial role during the siege of Sønderborg is a vivid testimony to the often concealed power of princesses, who, instead of being a sidekick to their spouses, started themselves to kick if necessary.

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Bodiam – A Cultural Biography

Professor Matthew Johnson of Northwestern University takes a look the iconic Bodiam Castle.

Many readers of the Castle Studies Trust blog will be only too familiar with Bodiam Castle.  It is the most-discussed late medieval castle in England, and probably in Europe.  Over the last ten years I have worked with a team of researchers from Northwestern University and the University of Southampton, in partnership with the National Trust.  We carried out a new survey of the building, a topographical and geophysical survey of the surrounding landscape, and a synthesis of the extensive ‘grey literature’ on the site.  Our work was published in the 2017 volume Lived Experience in the Later Middle Ages; digital copies are freely available here.  We deliberately avoided older debates, and instead stressed a landscape of work and the variety of lived experiences of different people as they worked and moved around the castle and local landscape.

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In this short blog post, I want to highlight one point:  Bodiam needs to be understood as a multi-period site and landscape.  One of the mistakes of the old ‘defence vs status’ debates was to see Bodiam simply as a creation of the 1380s and of one man, Sir Edward Dallingridge.  Our work suggests rather that the building and its surroundings form a distinctive place with its own cultural biography that should be understood over the very long term, from the Palaeolithic to the WWII pillbox.  It is a place that has seen reworking and recasting by different social groups over the centuries and even over the millennia.

The castle viewed from the N, photo taken from the older manorial site, also known as the ‘Gun Garden’ or ‘viewing platform’.  The floodplain of the Rother can be seen behind the castle, with the Weald rising up beyond and the linear village of Ewhurst Green strung out along the horizon.

The stone fabric of the castle does, indeed, date largely to the 1380s, and the use-life of the stone structure was relatively short; it was probably derelict and rarely used by the end of the 15th century.  However, its story is not just that of one man.  Bodiam was a manor of the Wardedieu family, which Edward inherited through his marriage to Elizabeth Wardedieu.  Alice Beauchamp, a wealthy widow and subsequently warden of the infant king Henry VI,  married John Dallingridge, son and heir of Edward; John died soon after his father, and Alice became chatelaine of the castle for 35 years until her death in 1443 (Johnson 2020, 321).  Usually presented as the creation of a single powerful man, Bodiam then was one of the residences of a powerful woman for much of its active use.  The elaborate stacked, double suite of ‘private’ chambers at the upper end of the hall needs to be understood in this gendered context.

Much of the internal fabric, and most of the barbican, was ‘robbed’ of building stone in succeeding centuries; many visitors stopped to leave their mark in the form of graffiti.  In the 1830s, ‘Mad Jack’ Fuller bought and restored the site and landscape.  Fuller’s wealth came in part from his ownership of enslaved people on plantations in Jamaica, as the recent National Trust report describes.  In the 1920s, the castle was restored again by ex-Viceroy of India Lord Curzon; Curzon of course was also responsible for the restoration of the Taj Mahal.  His activities at Bodiam included the failed construction of a cricket pitch (the selected site, which he named ‘the tiltyard’ but which was in fact the basin of the old millpond, was not an ideal choice).  The later cultural biography of Bodiam, then, is part of a story of colonialism and postcolonialism.

University of Southampton students surveying what Curzon termed the ‘tiltyard’, in reality the former millpond, in April 2010.  The castle and WWII pillbox are in the background. 

However, it is the prehistory of the site – its enduring importance as a critical place in the landscape – before the 1380s that most fascinates me.  The castle itself was ‘fitted in’ to an earlier framework of manorial site, village tenements, river crossing and wharf.  The whole assemblage sits at the junction of the Weald and the Rother Valley. The Kent and Sussex Weald, with its rolling hills, heavy clay soil and extensive woodland, contrasts with the floodplains below, running out to Romney Marsh.  Climatic variation and the troubled history of land reclamation has meant that at different times, the valley has been shallow estuary, marshland, or fertile fields (it will return to shallow estuary in 100 years if climate change continues).  Bodiam sits at the lowest crossing point on the river Rother, on a N/S Roman road, at a point which was a ford but which had a bridge from the 12th century onwards.

When I lecture on Bodiam, I like to suggest to audiences primed for discussion of knights, gunports and the Hundred Years War that the critical moment in the biography of the Bodiam landscape is not the 1380s, but rather the Early Bronze Age, when the complex interaction between human and environment meant that peat accumulation in the valley stopped and was replaced by alluvium.  And I like to go back still further, to a time in the deep past when the valley was some metres deeper and the surrounding hills some metres higher, giving a less comfortable and more rugged feel to the landscape.

Jacquetta Hawkes (1967) famously said that ‘every generation gets the Stonehenge it deserves – or desires’; the same, arguably, is true of Bodiam.  The Bodiam for our generation is, in part, a place of cultural biography and long-term climatic change, where humans have worked with and through the landscape to create, maintain and transform a place that has had an enduring importance over the millennia.

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References

Hawkes, J., 1967. God in the machine. Antiquity 41, 174-80.

Johnson, M.H. (ed.) 2017.  Lived Experience in the Later Middle Ages:  Studies of Bodiam and Other High Status Sites in South East England.  St Andrews, Highfield Press. 

Johnson, M.H. 20201.  Bodiam and the Canterbury Tales:  some intersections.  Medieval Archaeology 64:2, 302-329.  https://www.tandfonline.com/doi/full/10.1080/00766097.2020.1835273

Haverfordwest’s town wall revealed?

Neil Ludlow and Phil Poucher of DAT look at the results of the investigation at Haverfordwest Castle by Dyfed Archaeological Trust (DAT), as part of a major infrastructure scheme embracing the castle and its setting, has revealed what may be part of the medieval town wall, long thought to have been entirely destroyed.

The remains of the castle still dominate views of the town, particularly from the main eastern approach, crowning a steep bluff overlooking the Western Cleddau river. Founded around 1110 by one Tancard, a Flemish colonist, the castle appears to have begun as a partial ringwork and bailey, perhaps adapted from an Iron Age hillfort. Fortification in stone began under Tancard’s grandson Robert FitzRichard, a decade or so either side of 1200, with the erection of a subrectangular donjon; a curtain wall with at least one round mural tower was later added, possibly by the younger Marshal earls of Pembroke between 1219 and 1245. The castle was transformed into a palatial residence with the addition of an integrated suite of apartments of the highest quality, including hall and chamber-block ranges, and a terraced garden enclosure; they are traditionally attributed to Edward I’s queen Eleanor of Castile who received the castle and lordship two years before her death in 1290. The outer ward was also walled in stone, probably during the early fourteenth century. Although it played no part in the second Civil War of 1648, the castle was partially slighted on Cromwell’s orders and was subsequently used as a gaol, which closed in 1878.

Open to the public since 1970, and housing the town’s museum and County Record Office – but still perhaps an under-valued asset – the castle is now the subject of an enhancement programme to improve access, carry out essential repairs and redevelop the museum. The scheme extends to the castle’s setting, with improved landscaping and restoration of the surrounding burgage-plot boundaries. Preliminary archaeological work includes geophysical survey and test-pit recording.

Figure 1: The walling and archway from northeast. The castle donjon is at far left.

Investigating the castle exterior in early 2021, at the summit of the steep bluff, Andy Shobbrook of DAT came upon a stretch of walling that appears to have evaded previous investigations. Now of no great height, but probably truncated, it is pierced by a wide segmental arch of convincingly medieval form (Fig. 1). Although absent from published plans and descriptions of the castle, it is shown on the large-scale 1:500 map of the town produced by the Ordnance Survey in 1889, on which it is labelled ‘Arch’ in the Gothic script reserved for antiquities (Fig. 3). It lies just within the scheduled area of the castle, corresponding with its boundary, and appears to be in a stable condition.

Figure 2: Plan showing the conjectured layout of Haverfordwest in c.1300

The walling may be part of the medieval town wall rather than the castle defences. The town of Haverfordwest, which is notable for its three medieval parish churches – unique in Wales – was founded soon after the castle and by the close of the Middle Ages had become the de facto county town of Pembrokeshire. Defended by an earthen bank and ditch from an early period, probably before 1200, it was walled in stone after the issue of a murage grant in 1264. The defended area was relatively small, immediately next to the castle and always known as the ‘Castleton’ – while the extensive suburb around the extra-mural marketplace to the south received fortified gateways, they were never connected by any solid barrier (Fig. 2). The town wall had largely disappeared by 1700 and, while the gatehouses survived rather longer, the last were removed at the end of the eighteenth century.

Figure 3: An extract of the Ordnance Survey 1:500 map of Haverfordwest, of 1889,
showing the castle and walling (labelled ‘Arch’).

Vestiges of the wall were apparently still detectable in 1900 but all traces were thought to have been lost soon afterwards. Stretches of its former line are marked by property boundaries but its entire course is not precisely known, nor the points at which it connected to the castle defences. The walling discovered in 2021 butts against the donjon at the northeast corner of the castle inner ward, and runs northwest for 5 metres before petering out. The remains of a return at its northwest end correspond with a 90° turn shown on the 1889 map, on which it is shown to then run north-eastwards before turning west to continue along the outer edge of the castle’s northern ditch. But the medieval wall must have deviated from this line at some point, to run northwards to the eastern town gate. The arch is 3 metres wide but was probably always too low – and perhaps too wide – to represent an entry. Its function may simply have been to drain the area immediately to the west, which slopes steeply downhill towards the east and seems to have been a continuation of the castle ditch where it ran out at the crest of the bluff (Fig. 3). Two phases of work within the arch are possible, suggesting it was modified and perhaps narrowed at some point.

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Dún an Óir Castle: an uncertain future

Dr Sarah Kerr of Trinity College Dublin discusses the ongoing project to look at the impact of climate change on castles with a focus on the ones in West Cork, as they are battered by Atlantic storms.

Over the past two years, two small grants (Research Incentive Scheme, Trinity College Dublin, Ireland; and Higher Education Innovation Fund, UK) has funded research into the impact of climate change on built heritages, and the identification of those most vulnerable, particularly in West Cork, in the south-west of Ireland. Dún an Óir is one such castle at risk, on the edge of Ireland, on the brink of the West Cork cliffs and at the mercy of the increasingly frequent Atlantic storms and high winds.

Dún an Óir is a castle at risk, on the edge of Ireland, on the brink of the West Cork cliffs and at the mercy of the increasingly frequent Atlantic storms and high winds. Dún an Óir is an Irish tower house, a type of stone-built castle, smaller than the sprawling castles built by the Anglo-Normans, such as Trim, County Meath and, indeed, serving a different purpose. The relative small size of tower houses placed their construction within the financial reach of lords, emerging gentry and merchants in both rural and urban areas. Tower house construction commenced on the island of Ireland (Ireland hereafter) in the mid-fourteenth century and flourished in the fifteenth and sixteenth, construction ceasing by 1650. Their abundance led Terry Barry to state that Ireland was ‘the most castellated country in Europe in the late middle ages’ (Barry 2008, 129) or at least ‘one of the most castellated parts’ of the Irish and British Isles (Cairns 1987, 31; O’Connor 1998, 25). If so, then Munster in the south-west of Ireland was a focal point of this activity. The West Cork area in the south-western extent of Munster contains 47-known tower houses, many concentrated along the jagged and island-dotted Atlantic coast. The West Cork tower houses are of particular interest as they are the only castle type remaining in the region; plus, contemporary written evidence allows the majority to be ascribed to a certain clan.

Dún an Óir (Doonanore when anglicised) is located on the island Oileán Chléire (Clear Island), approximately 13km from the Irish mainland. It was built by the O’Driscoll clan in the mid-sixteenth on a coastal promontory (Figure 1). Located on the coast, along with several other known O’Driscoll tower houses, its occupants could oversee the movement of goods through Roaringwater Bay as well as charge passing vessels for anchorage, victualing and exploitation of the waters (Figure1). 

This once strategic position is Dún an Óir’s Achilles heel. The building and its immediate landscape are precarious, unconsolidated and unprotected (Figure 1). Exposed on a partially collapsed promontory, its long-term survival is unlikely and our time to understand it short.

Figure 1: Photograph looking north across Roaringwater Bay towards the Atlantic showing Dún an Óir on a rocky promontory.

Dún an Óir comprised four-storeys rising from a rectangular ground-plan. Access was through the south wall, although the east wall faced the neck of the promontory (where it connected to the remainder of the island). Much of the south wall has collapsed yet a garderobe tower remains to the east of the door (Figure 2). Above the doorway a mural staircase (built within the thickness of the wall) can be seen leading to at least the first and second floors. There is a vaulted ceiling between the second and third floors in the form of three pointed arches separated from one another by overlapping slabs.

Figure 2: Dún an Óir tower house, from the southeast, showing the mural staircase extending upwards along the south wall (with thanks to Finola Finlay and Robert Harris for the photograph).

A significant and surviving feature of Dún an Óir is its bawn (curtain wall): a stone wall which in this case abuts the tower house (rather than surrounding it) and stretches west to enclose the remainder of the promontory (Figure 3). Vicky McAlister’s recent book on tower houses indicates that the survival rate of bawns is low compared to the tower houses themselves (McAlister 2019, 22), recalling earlier suggestions that the current 1 in 5 survival rate may be representative of their former inclusion. Dún an Óir is a relatively rare example of preserved ancillary buildings within the bawn. Although they remain only as overgrown footings, there appears to be a kitchen with oven, and two more apparently feature-less buildings that appear to be contemporaneous with the bawn wall (Figure 3).

Figure 3: A simple plan of Dún an Oir tower house, bawn, and ancilliary buildings. The proximity tit he promontory edge is clear.

Dún an Oir’s bawn reaches to the edge of promontory, almost certainly to be further damaged or lost in this lifetime. With this seemingly fixed future, the onus shifts to the researching community in the present to document what we can: this is discussed further in a recent paper on the castle (Kerr 2019). The erosion to the promontory renders further buildings survey, as well as geophysical survey or excavation, no longer safe. Therefore, the next steps of fieldwork may include airborne LiDAR. Greater exploitation of innovative surveying methods may overcome the difficulties posed by the physical landscape and allow the tower house, bawn and ancillary buildings to be understood to a greater depth before the inevitable happens.

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Barry, T. 2008. The study of medieval Irish castle: a bibliographic survey. Proceedings of the Royal Irish Academy: Archaeology, Culture, History, Literature 108(C), 115–36.

Cairns, C. 1987. Irish tower houses: a Co. Tipperary case study, Group for the Study of Irish Historic Settlement.

Kerr, S. 2019. Reconnecting Cultural Landscapes: Dún an Óir, West Cork, Ireland, Landscapes, 20:2, 160-177, DOI: 10.1080/14662035.2020.1861725

McAlister, V. 2019. The Irish tower house, Manchester University Press.

O’Conor, K. 1998. The archaeology of medieval rural Settlement in Ireland, Discovery Programme Monographs.

Barns in the Bailey: Agricultural buildings within castles

Castles were more than military sites, being political, judicial and economic centres too. Duncan Berryman of Queen’s University Belfast looks at one of those aspects, the important but little studied area of agricultural buildings in castles.

The domestic considerations of castles were as important to daily life as their defensive functions. Castles were also the centres of estates; Clare Castle (Suffolk) is a good example of an estate centre with manors in the surrounding region and further afield while Caister Castle (Norfolk) was the centre of a much more compact estate. Manorial centres were generally undefended courtyards of domestic and agricultural buildings. However, many of these were moated sites and their lack of defensibility might be debated. Sites such as Chalgrove (Oxfordshire) and Coolamurry (Wexford) had substantial moats and may have had complex bridges (Page et al. 2005; Fegan 2009). These complexes saw high-status accommodation sitting alongside the barns and animal housing that served as the manorial farmyard. Many smaller castles would have been the centres of smaller estates and would have also functioned as manorial centres. Agricultural buildings were vital to this operation and would have been found within baileys or associated enclosures. To investigate these buildings, it is essential to take a multidisciplinary approach by combining archaeology with documentary and pictorial evidence. The agricultural buildings have often been left unexcavated as they are seen as less important, and less interesting, than the domestic complexes.

Artistic reconstruction of Clough Castle (Down). Many motte and baileys would have had a similar appearance, often with timber structures on the motte instead of the masonry buildings presented here.

Documentary sources related to Ireland indicate that many smaller castle sites had agricultural buildings within the surrounding area. This is clearly illustrated at Cloncurry (Kildare), where an extent records that beside the motte was “an old haggard close [farmyard] in which there are two small granges [barns] each of eight forks … [t]here is also there, beside the gate an ox-house … [and t]here is a dovecote” (Murphy & Potterton 2010, 175). There is also a record of a barn of ten forks at Castlemore (Carlow), as well as a mill and other timber and masonry buildings (O’Conor 1998, 32). The forks referred to in these accounts are probably the cruck blades of the barn, thus ten forks produce a nine-bay barn that could be the equivalent size of a barn like Bredon (Worcestershire). At Lough Merans (Kilkenny), the motte sat on a promontory in the lake and had an associated bailey containing a granary, stables, and a sheepcote (O’Conor 1998, 30). The motte of Inch (Tippararery) also had a granary and sheepcote, additional buildings were stables, a fish-house, a dovecote, and a malt kiln (O’Conor 998, 29). These examples suggest that, in Ireland, castles were playing important roles as the centres of manorial farms and wider estates. The perceived need for a defensive motte may have been carried over from an earlier period, but it continued with the construction of tower houses in the fifteenth and sixteenth centuries (McAlister 2019, 28-35).

Bredon Barn (Worcestershire). Barns of a similar size were found within castle baileys. They would have been constructed from masonry or timber

A brief survey of larger castles in England does show that these castles had a small number of agricultural buildings. The main buildings identified were stables, dovecotes, barns, and granaries. These buildings are unlikely to have functioned in the same way as they did in rural manorial centres, but they are a reminder that some agricultural processes occurred within the castle. Stables were obviously for housing the riding horses of the lord or king and their entourage, but they probably also housed the cart horses used by the castle staff to bring goods in from the market. There are records of stables at Hereford, Leeds (Kent), Leicester, Lincoln, Nottingham, and the stables of Kenilworth (Warwickshire) are still extant (Colvin 1963). The dovecote was an important source of food in the form of squabs (young pigeons). A dovecote was recorded at Dorchester (Dorset) and one has been identified in the south-west tower of Bodiam (Sussex) (Colvin 1963; Thackray 2003). The existence of barns might suggest that sheaves of wheat or barley were being brought into the castle and threshed there, providing grain for flour and straw for the stables and other floors around the castle. There is evidence for barns at Acton Burnell (Shropshire), Bamburgh (Northumbria), Hadleigh (Essex), Weoley (Warwickshire), and Pontefract (Yorkshire) (Colvin 1963; Emery 2000; Roberts 2002).

The stables of Kenilworth castle (Warwickshire). This was a particularly grand building, but stables were vital for the lordly lifestyle.

The c.1610 plan of Castle Hedingham (Essex) indicates that there may have been an agricultural complex beside the main castle enclosure (Emery 2000, 113). To the top of the map are buildings labelled stable and barn and an area marked barnyard, in manorial sites this would indicate a complex of crop storage buildings including several barns and a granary. Returning to Clare Castle, the 1325 accounts of the constable indicate that there were a pigsty and poultry house within the castle compound (Ward 2014, 64).

Agricultural buildings are found in areas away from the main domestic complex of the castle, and these areas are often left unexcavated. They were most often made of timber, and thus leave little trace in the archaeology compared to the stone-built structures elsewhere. It is possible that there were more agricultural buildings within castles, or close to them, and they have not yet been identified. This research highlights the importance of using documentary and pictorial sources alongside archaeology and reminds us that lesser castle complexes may have been surrounded by a significant range of buildings.

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References

Colvin, H.M. (ed.) 1963, The History of the King’s Works Vol I & II (London: Her Majesty’s Stationary Office).

Emery, A. 2000, Greater Medieval Houses of England and Wales II (Cambridge: Cambridge University Press).

Fegan, G. 2009, ‘Discovery and excavation of a medieval moated site at Coolamurry, C. Wexford’, in C. Corlett & M. Potterton (eds), Rural Settlement in Medieval Ireland in the Light of Recent Archaeological Excavations (Dublin: Wordwell Books).

McAlister, V. 2019, The Irish Tower House: Society, Economy and Environment c.1300–1650 (Manchester: Manchester University Press).

Murphy, M. & Potterton, M. 2010, The Dublin Region in the Middle Ages: Settlement, Land-Use and Economy (Dublin: Four Courts Press).

O’Conor, K.D. 1998, The Archaeology of Medieval Rural Settlement in Ireland (Dublin: The Discovery Programme).

Page, P., Atherton, K. & Hardy, A. 2005, Barentin’s Manor: Excavations of the moated manor at Harding’s Field, Chalgrove, Oxfordshire 1976–9 (Oxford: Oxford Archaeology Unit).

Roberts, I. 2002, Pontefract Castle: Archaeological Excavations 1982–86 (York: West Yorkshire Archaeology Service).

Thackray, D. 2003, Bodiam Castle (Swindon: The National Trust).

Fragile symbols: gunpowder and castle walls

Dr Peter Purton, FSA, Castle Studies Trust trustee and author of recent works on medieval sieges and medieval military engineers looks at his latest area of research, later medieval fortifications and the impact of the introduction of gunpowder.

Castle studies were once ruled (in England at least) by wealthy amateurs, mostly male (Ella Armitage a stand-out exception) and many with military backgrounds. Every aspect of a castle, for them, was determined by military thinking. The late twentieth century counter-attack turned this on its head, stressing the symbolic role of castle-building as expressions of status and power. Some people challenged any suggestion that changes were driven by the need to upgrade defensive capability; and the same argument has been applied when guns arrived on the scene.

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Those keen to argue the superiority of the English can always point to the first adoption (in Europe – the Chinese were centuries ahead) of gunpowder, and its first use for war. It’s also true that the English were the first to adapt fortifications to use guns, from the mid-fourteenth century, a little ahead of the Low Countries followed by the French, all places affected by the devastating impact of the struggles we bundle up in the title of the Hundred Years war (1337-1453).

Gun loop at the west gate of Canterbury, Kent

Were loops created for guns also symbolic? If you take account of the historical reality of the time, this argument surely evaporates in a puff of (gun)smoke. I’m working on a new history of changes in fortification in the age of gunpowder with Dr. Christof Krauskopf and we delivered a paper at the (virtual) Leeds IMC in July 2020 addressing this question. We can’t answer the question without knowing the context, and what the builder wanted. The first is usually evident, the second is irretrievable. Across southern England from the earliest days of the war there were frequent seaborne raids by the French and their allies that caused local devastation and serious embarrassment (and loss) to the English crown. People could not know when and where the next attack would come. The response was the preparation of defences designed to use guns (at the time, they were not powerful enough to harm stone walls) from East Anglia (the Cow Tower of Norwich, for example) to Devon (Hawley’s Fortalice at Dartmouth), usually adapting existing defences but often building anew. The royal ‘architect’ (an anachronistic shorthand) Henry Yevele was directly involved in the erection of the Westgate and the reconstruction of the city walls at Canterbury and at private castles in Kent (Cooling, for example). Southampton, having been burnt to the ground by the French, underwent extensive reconstruction of its defences, including (early in the fifteenth century) one of the first gun-towers (the God’s House tower).

Cooling Castle, Kent, Outer Gatehouse

Amidst all this very expensive work, in 1385, the castle at Bodiam (Sussex) was put up for Sir Edward Dallingridge, set in a lake and pierced with gun loops and now a picture-postcard National Trust attraction. It has been the centre of a battle lasting longer even than the hundred years war. Forty years ago, the late Charles Coulson famously demolished its military pretensions by pointing out its many flaws from a defensive viewpoint. Bodiam became the peaceful retirement home for a military veteran.

Bodiam Castle courtesy of Wyrdlight.com

Sometimes you only see what you want to see. Actually, Dallingridge wasn’t retired: he was commissioned to review the defences of the coast, for the king, and was actually wounded in a French attack. His gun loops may not have worked very well and his lake could have been drained – but a French raiding party was unlikely to hang around long enough to find out. In the context, the most that can be said is: we don’t know what he intended.

England swiftly lost its leading position in the race to build fortifications adapted for and against artillery as it became significantly more powerful during the course of the next century, a time when the gap between what princes and their subjects could afford expanded greatly. But many nobles did make provision for guns, and kings still put comfort first (Edward III’s work at Windsor). Between the two extremes of fortresses with evident military purpose and castles designed as palatial homes, others tried to provide for both functions, with numerous examples across the continent.

Perhaps that was what the medieval castle had always been?

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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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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