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.
Mondern day Lincoln Castle from the west copyright Andy Tyner Photography on behalf of FAS Heritage and Lincolnshire County CouncilLincoln 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.
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.
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.
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.
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.
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.
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.
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.
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.
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?
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:
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;
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 ProjectFIGURE 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 BrownFIGURE 4. Micromorphologyor ‘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.
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.
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.
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.
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?
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).
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.
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)
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
