LiDAR and Early Medieval Settlement in Counties Roscommon and Leitrim: a New Angle on Early Medieval Landscape Studies.

Abstract

Early medieval settlement has long been the focus of both archaeological and historical

research, however, there are still substantial gaps in our knowledge, particularly in relation

to the largely unexplored Irish midlands. Parts of county Roscommon were identified by

Matthew Stout as an area of very high ringfort density (Stout 1997, 93), however, with the

exception of the important royal complex at Rathcroghan, relatively little research has been

conducted in the area. The application of LiDAR analysis to the study area presented an

opportunity to break new ground in two ways: firstly as a means of investigating the early

medieval landscape of a relatively unexplored part of the country; and secondly, as a pilot

study into the use of LiDAR data as a means of examining early medieval Irish settlement.

This data was combined with aerial photography and historic mapping to find and identify

previously unrecorded archaeological monuments which potentially date to the early

medieval period (primarily ringforts). This article is a summary of the results found during

the completion of an MA thesis submitted in August 2012 to the School of Archaeology,

University College Dublin; and will outline the nature of the project and discuss some of the

findings.

Introduction For many years, early medieval settlement has been the subject of considerable research

interest as the impressive bibliography compiled by EMAP1 (Harney et al. 2010)

demonstrates. However, the project undertaken as part of the author's MA thesis takes it in

a new direction as it constitutes one of the first Irish studies to use LiDAR (Light Detection

and Ranging) survey data as part of a targeted study of the Irish early medieval landscape.

LiDAR measures the height of the ground surface and other features by scanning a pulsed

laser beam from a low-flying aircraft over the survey area (Bewley et al. 2005, 637). As

LiDAR reads elevation data in addition to locational data, it enables the creation of high-

resolution topographic maps which allow us to identify subtle variations in the ground

surface created by earthworks and other features (Chapman 2006, 58).

1 Early Medieval Archaeology Project

1

This type of data has become increasingly popular in recent years due to its ability to reveal

previously 'invisible' archaeological features2 in the landscape, with the added benefit of

being able to penetrate foliage and therefore provide a model of the bare earth surface

(Megarry 2011, 32). The last 4 to 5 years in particular have seen a proliferation of Irish

LiDAR-based projects (Shaw & Corns 2011, 84). Despite the recent popularity of LiDAR

within the realm of Irish archaeology, to date, much of this type of research has been

focused on already well-known archaeological landscapes such as the Hill of Tara (Corns &

Shaw 2009) or Brú na Bóinne (Davis et al. 2010). Instead, this study utilises the data to

investigate early medieval settlement within a specific - yet arbitrary as far as archaeological

remains are concerned - area of counties Leitrim and Roscommon.

Study Area Location Commissioned by Leitrim County Council and the National Roads Authority, the LiDAR

dataset which forms the basis of this research was flown as part of the consultation phases

of the proposed N4 Carrick-on-Shannon to Dromod road scheme, and this survey dictates

the location of the project.

LiDAR survey data can come in a range of different resolutions, and two different

resolutions (both produced by Ordnance Survey Ireland) were used over the course of this

research. The original 2m-resolution dataset was kindly provided by Leitrim County Council

and covers an area of approximately 140km². A higher 0.5m resolution dataset was funded

by the Roscommon County Council Heritage Research Bursary 2012 and covers an area of

approximately 30km² (Figure 1). Ultimately, the real value of the higher resolution dataset

was the improved quality and sharpness of the images and the enhanced visibility of the

monuments when reproduced (Figure 2).

2 Unlike geophysical survey, LiDAR cannot detect features that solely have sub-surface remains, therefore it can only reveal archaeological features which have topographic expression, however slight they are.

2

Figure 1: Study Location

Figure 2: Resolution Comparison - Lackagh, Co. Roscommon

Topography

The study area is dominated by drumlins, the small rounded hillocks formed by retreating

ice during the last Ice Age. As is characteristic of the drumlin belt, the area is home to

numerous lakes, and the study area is no different, with a total of seventeen lakes ranging

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from the relatively substantial Lough Eidin in the barony of Boyle to much smaller bodies of

water such as Lough Nanoge or Costre Lough. The River Shannon effectively bisects the

study area and provides a natural boundary between the counties of Roscommon and

Leitrim. Other substantial waterways in the area include Killukin River, Boyle River and the

Jamestown Canal which was constructed in the 1770s (Delaney 1987, 40).

Territorial Units

269 townlands are either wholly or partially represented, although only very small portions

of some of those on the periphery are contained within the study area. In addition to nine

civil parishes, the area also comprises parts of five baronies: Roscommon, Boyle and

Ballintober North in Co. Roscommon; and Mohill and Leitrim baronies in Co. Leitrim.

Corry, Co. Roscommon is the largest townland in the study area and contains ten ringforts3

in addition to a crannóg within the adjoining Lough Corry, although this is not attributed to

the townland itself. The townland of Kiltoghert, Co. Leitrim is the second largest townland in

the study area and with fourteen ringforts and a crannóg, contains the highest volume of

early medieval settlement.4

Archaeological Evidence There are a total of 495 recorded archaeological sites within the study area (Table 1), the

vast majority of which relate to the early medieval period. Of course this may be a result of a

survival or identification bias rather than a lack of activity in the area during earlier and later

periods.

Table 1: Recorded Monuments in the Study Area (per Period) (after http://www.archaeology.ie/)

PERIOD Count of SMR Percentage Prehistoric 17 3% Early Medieval 280 57% Early Medieval (Possible) 157 32% Medieval/Late Medieval 18 4% Post-Medieval/Modern 23 5%

Grand Total 495

Evidence for early medieval settlement is both plentiful and varied with the number of

potential sites totalling 437, and the number of ringforts significantly outnumbering any of

the other monument types. Clearly each monument has not been scientifically dated and so

the identification of the sites is based largely on the classifications contained in the online 3 Two of which were discovered as part of this project 4 Five of which were discovered as part of this project

4

database of the Sites and Monuments Record (http://www.archaeology.ie/). Some further

investigation was carried out in relation to those monuments that had undergone excavation

and those with more complete records held in the National Monuments Archive. The early

medieval sites are scattered throughout the study area (Figure 3), although the south-

eastern corner is very sparsely populated which again could be the result of preservation

issues rather than proof of a lack of activity.

Figure 3: Recorded Monuments in the Study Area

(after http://www.archaeology.ie/)

Previous Research "If the sources for the early history of Munster are meagre, those for Connaught before

AD800 are almost non-existent" (Ó Cróinín 1995, 59). Substantial research into early

medieval Ireland has been conducted, particularly in recent years; however, investigations

into this period within the counties of Leitrim and Roscommon - and this study area in

particular - are relatively sparse. This is highlighted by EMAP's recent collation of data - the

Gazetteer of Site Descriptions - relating to the period where only three Roscommon sites

are mentioned and County Leitrim does not feature at all (Kerr et al. 2010, 608-615).5

Preliminary work was carried out by Will Megarry on a portion of the study area as part of

the proposed road scheme. This work was concentrated mainly on the N4 route itself and

5 Of course this is a reflection on the lack of archaeological excavation in the area rather than any failing on the part of EMAP

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buffer zones of 50m and 100m around it, 41 townlands were surveyed and 12 new potential

monuments discovered, 9 of which are potential ringforts (Megarry 2011, 34).

Excavations

Perhaps the most significant excavations for this study area are those which took place in

Cloongownagh townland, Co. Roscommon in 1999 and 2003 as part of the national roads

building programme. A ringfort (SMR: RO011-160001) was partially excavated in 1999

(Licence 99E0193) and produced radiocarbon dates of cal. AD 641 - cal. AD 757 and cal.

AD 896 - cal. AD 1029, in addition to faunal remains, two rotary quern-stones and a piece of

slag (http://www.nra.ie/Archaeology/). The 2003 excavations (Licence: 03E1770) of a pit

and/or charcoal-making site produced radiocarbon dates of cal. AD 900 - cal. AD 1040

(http://www.nra.ie/Archaeology/).

Methodology The raw data were processed and imported into ArcGIS 9.36 where several hillshade

models were created in order to artificially light the surface from different angles. It is these

effects of light and shadow that help to capture and highlight the almost imperceptible

changes in topography that can indicate the presence of an archaeological monument. The

surface was then systematically examined for evidence of any potential archaeological

features, in particular ringforts within which the majority of the early medieval population

lived (Stout 1996, i).

All potential ringforts (known and 'new' monuments) were measured on the LiDAR surface

and their dimensions (internal and overall diameters) recorded. Locational data such as the

degree of slope and altitude were also recorded.

The Results The prospection for 'new' early medieval archaeological monuments resulted in the

discovery of 153 potential monuments, 98 of which were identified as 'Probable Ringforts',

54 as 'Possible Ringforts' and 1 as an 'Ecclesiastical Enclosure'. This constitutes a total

increase of approximately 44% in the number of ringforts within the catchment area,

bringing the total from 335 to 487.7 On a barony by barony basis, the number of monuments

has increased as follows:

6 A Geographical Information System (GIS) 7 The ecclesiastical enclosure has been omitted from these calculations as it is technically not a settlement site; the figure also excludes crannógs

6

Table 2: Known and 'New' Monuments Per Barony8

Barony Known New Grand Total Ballintober North 30 16 46 Boyle 126 54 180 Leitrim 160 67 229 Mohill 9 9 18 Roscommon 10 3 14

Grand Total 335 149 487

The newly discovered monuments have a significant impact on ringfort density in the area

and undoubtedly also have implications for our understanding of ringfort distribution in the

wider landscape. Prior to this survey being carried out, there were 335 known (potential)

ringforts in the study area, a density of 2.39 ringforts per km². Following this survey, this

figure rises to 3.46 ringforts per km², considerably higher than the mean density of 0.55 per

km² for the country as a whole (Stout 1996, 59). However, the baronies of Roscommon and

Leitrim were identified by Stout as being 'zones of very high density' with 1.77 and 1.31

ringforts per km² respectively (Stout 1997, 93), and so a relatively high figure is not

surprising in itself. Even so, the results of this LiDAR survey clearly significantly affect the

concentration of monuments and therefore the density of ringforts within the study area

(Figure 4). Ultimately this will have a knock-on effect on our understanding of early medieval

settlement patterns and could influence estimates of population size both within the study

area and on a larger scale. In particular, there can be a dramatic impact on our

understanding of early medieval settlement at a local level, with the pattern of settlement

being significantly altered in many townlands (Figures 5-7).

8 Minimal parts of Mohill and Roscommon baronies are represented within the catchment areas which accounts for the significantly lower volume of sites.

7

Figure 4: Post-Survey: Known and 'New' Early Medieval Monuments

Figure 5: Before and After - Tumna Townland, Co. Roscommon

8

Figure 6: Before and After - Cortober Townland, Co. Roscommon

Figure 7: Before and After - Mullaghmore Townland, Co. Roscommon

Applying the Results While the LiDAR analysis has physically added to the archaeological record in the study

area, it is important that the research does not stop here. Instead, it is imperative that this

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knowledge be applied in order to better our understanding and interpretation of early

medieval settlement. A number of the findings are presented below.9

Annaghmona Townland, Co. Roscommon

A newly discovered monument in the townland of Annaghmona, Co. Roscommon is one of

the largest potential ringforts within the study area. With an internal diameter of

approximately 75.6m, RBO-266N has a particularly interesting and possibly significant

location on a promontory overlooking Lough Eidin (Figure 8). This monument is in relative

isolation as it is located on a veritable island as the land around it projects out into the lake

with only a narrow band of low-lying ground joining it to the mainland. Given its size and

location, this may correspond to Matthew Stout's 'Cluster 4' ringforts that fulfilled a "military,

judicial or administrative role" within the region (Stout 1991, 240). There are similarly large

enclosures at Kiltoghert, Co. Leitrim; and Deerpark and Ballinvilla Co. Roscommon.

Figure 8: Newly Discovered Potential Ringfort in Annaghmona Townland

Low Density Example: Fearnaght, Co. Leitrim

There is one particular zone of low to zero density located in the southeast of the study

area. Comprising the relatively substantial townland of Fearnaght, Co. Leitrim

(approximately 1.56km²), many of the townlands surrounding it are also very sparsely

settled, with most of them containing one or no early medieval sites.10 The present

9 More detailed analysis can be found in the author's MA thesis (Curran 2012) 10 Only Gortinee contains two, both of which were discovered during the course of this project.

10

topography is not particularly striking and there is no obvious reason for the absence of

settlement evidence in this south-eastern portion of the study area. With the possible

exception of a cairn (SMR: LE035-005) on the Aghintass/Finnalaghta townland border

which may actually be 17th century in date (http://www.archaeology.ie/), there is no

evidence of even prehistoric settlement.

Fearnaght townland itself has the remains of a pillar stone and bullaun stone (SMR: LE035-

017 and LE035-018 respectively) which may point to the former existence of an early

medieval ecclesiastical site, although there is no indication of this from the LiDAR raster

surface (2m-resolution), aerial photography or historic maps

(http://maps.osi.ie/publicviewer/#V1,603972,792800,6,4); and indeed none is listed on the

extensive (albeit not definitive) Monasticon Hibernicum database

(http://monasticon.celt.dias.ie/). Of course, LiDAR data is not 100% conclusive and there

could be sub-surface remains, or even surface remains which are obscured by the

substantial vegetation cover. However, even if there was a substantial ecclesiastical

presence in the area, it would not explain why there is no evidence of secular settlement

here.

It is also possible (although there is no suggestion of it on the OSI aerial photography or

historic maps) that the area may have been inhospitable or relatively inaccessible to the

early medieval population - perhaps this is where the bandits who were cast out of society

and the wild animals lurked (Bitel 1990, 34,35). Indeed there is some indication of this from

the placename evidence which paints a relatively inhospitable picture: 'Moherrevan' is the

Anglicisation of 'Mothar Riabháin' (Logainm.ie) and the Irish 'Mothar' translates as 'thicket;

jungle; wilderness' (eDil); Fearnaght itself is an Anglicisation of 'Fíodh Fhearnacht'

(Logainm.ie) with 'Fíodh' also having connotations of forestry (eDil); Corrascoffy is

translated as 'Chorr an Scafaigh' which has been taken to mean 'the round hill of the bare

patch of rocks' (Logainm.ie). Somewhat ironically 'Faulties' is translated in Irish as 'Na Fálta'

which means 'the enclosures' (Logainm.ie) so perhaps there are indeed sub-surface

remains to be uncovered.

Conversely, there are smaller townlands which contain a substantial number of sites, for

example, covering an area of just 0.18km² Lisfarrellboy, Co. Roscommon is one of the

smallest townlands yet it is home to six ringforts. Likewise, Lisnagat, Co. Leitrim covers just

0.17km² and contains four ringforts, one of which is bivallate.

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High Density Example: Danesfort, Co. Roscommon

The townland of Danesfort covers an area of approximately 1.6km² and contains a total of 7

ringforts with varying characteristics. As such, it provides an excellent opportunity to

investigate settlement hierarchy and to attempt to reconstruct how the townland may have

been organised within the early medieval period.

Of the 7 ringforts within the townland, one is bivallate (SMR: RO011-048) and has an

internal diameter of approximately 54.1m and an overall diameter of approximately 77.8m.

This ringfort occupies a prime location on the drumlin summit with commanding views over

the surrounding territory and other neighbouring settlements. Given its size, morphology

and location, this ringfort is potentially 'royal compatible' and is likely to have housed high

status occupants. A large univallate ringfort lies just 300m to the southwest (SMR: RO011-

046), on the border with the townland of Glebe and close to that of Killukin. A smaller

ringfort lies to the west of the bivallate example, towards the foot of the drumlin. These may

have afforded some element of protection to the higher status inhabitants of the bivallate

ringfort.

The remaining ringforts range in internal diameter from 22.7m to 33.8m and this, combined

with their location, points to them being the potential residences of the lower grades of

freeman such as the bóaire (cow lord) or ócaire (young lord) classes. The bóaire would

have owned their own land while the ócaire did not have their own land but leased it from a

higher ranked lord on an annual basis (Stout 1997, 112).

Ecclesiastical Sites

The coming of Christianity to the island of Ireland in the sixth century significantly altered

the physical landscape as churches, monasteries and ecclesiastical centres were

established throughout the country. There are a number of ecclesiastical sites still extant

within County Roscommon, some of which may have their origins in the early medieval

period. Perhaps the most notable of these is the site at Tumna which is still very much

evident today with the remains of two stone churches and the tomb of the founding saint.

Although an ecclesiastical enclosure is listed on the Sites and Monuments Database (SMR:

RO007-087003), the accompanying description states that "nothing of this feature can be

seen now" (Moore 2010). However, the LiDAR surface has revealed the possible location of

this enclosure, curving around the site to the south and east (Figure 9).

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Figure 9: 'New' Ecclesiastical Enclosure at Tumna, Co. Roscommon

Enclosures are a common feature of early medieval ecclesiastical sites (Aalen 1989, 93;

Ryan 2005, 88) and the identification of such a feature at Tumna is significant as it not only

points to its possible early medieval origins, but also helps to demarcate the area

encompassed by the site itself. Located on the banks of Lough Eidin and the River

Shannon, the enclosure appears to be incomplete, perhaps having been at some point

subsumed by the water to the north and west; or perhaps the river and lake themselves

complete the boundary. A similar enclosure can be seen at the ecclesiastical site located

within the townland of Attirory, Co. Leitrim.

Soil type, land tenure and the inherently holy quality of a place were just some of the

practical considerations to be taken into account when selecting a site for the building of a

church in the early medieval period (Bitel 1990, 17). Rivers, lakes and streams were often

more accessible and afforded safer passage between settlements than routes reliant on

travel through the interior (Bitel 1990, 30). In this regard, the ecclesiastical site at Tumna

occupies a prime position in the landscape with its location at a narrow fording point on the

banks of Lough Eidin. Indeed, it is located less than 300m from the banks of Cleaheen

townland, Co. Leitrim. This raises important questions about the scope of an ecclesiastical

settlement, e.g. did the site at Tumna serve the community on both sides of the lake or did

the water serve as a boundary? There are eight settlement sites that fall approximately

equidistant between the ecclesiastical sites of Tumna and Church Hill, Co. Roscommon.

Both churches are likely to have early medieval origins and may have been in existence at

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or around the same time; arguably either one (or both?) could have served the local

population.

Conclusion

Unlike the flat portrayal of the landscape by cartographic or photographic imagery, LiDAR

enables us to view the landscape as a two-dimensional surface, meaning that the

settlement evidence can be viewed as it lies topographically and we can therefore get a

sense of how the landscape looked and was physically experienced in the early medieval

period.

The LiDAR analysis demonstrated in this project has quite literally 'filled in the gaps' in the

landscape, gaps that we suspected - but could never prove - were there. Of course there

are undoubtedly monuments and archaeological features that LiDAR cannot pick up, and

perhaps a targeted study using a combination of LiDAR with geophysical and other

prospection methods could fill in even more of the gaps. With the application of this

technology to archaeological research, we are maximising the potential to enhance our

knowledge and understanding of early medieval settlement within the counties of

Roscommon and Leitrim, and of indeed within the whole of Ireland.

At the time of writing, all newly discovered potential monuments are in the process of being

reported to the National Monuments Service so that they can be evaluated and those

accepted will be added to the Sites and Monuments Record.

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Stout, M. 1996 Early Christian Settlement and Society in Ireland with Particular Reference to Ringforts. unpublished PhD thesis, Trinity College Dublin. Stout, M. 1997 The Irish Ringfort. Dublin: Four Courts Press. Websites eDil Fearnaght http://www.dil.ie/results-list.asp?mode=BAS&Fuzzy=0&searchtext=F%C3%ADodh&findlet=+&findcol=&sortField=ID&sortDIR=65602&respage=0&resperpage=10&bhcp=1 Accessed 09/08/2012, 9.13pm Moherrevan http://www.dil.ie/results-list.asp?mode=BAS&Fuzzy=0&searchtext=mothar&findlet=+&findcol=&sortField=ID&sortDIR=65602&respage=0&resperpage=10&bhcp=1 Accessed 09/08/2012, 9.05pm Logainm.ie Corrascoffy http://www.logainm.ie/30194.aspx Accessed 09/08/2012, 9.19pm Fearnaght http://www.logainm.ie/30244.aspx Accessed 09/08/2012, 9.11pm Moherrevan http://www.logainm.ie/30250.aspx Accessed 09/08/2012, 9.02pm Monasticon Hibernicum http://monasticon.celt.dias.ie/ Accessed 24/07/2012, 3.15pm National Roads Authority Cloongownagh Licence 03E1770 http://archaeology.nra.ie/Home/ViewResult/c9f0c082-30fe-4fb3-b303-4a5a41e7f1af Licence 99E0193 (1) http://archaeology.nra.ie/Home/ViewResult/707e1cb2-43ab-4718-ae4e-02f415b184fd Licence 99E0193 (2) http://archaeology.nra.ie/Home/ViewResult/5d01353e-15f3-4f6b-af42-1f2d08e911aa Accessed 05/07/2012, 4.49pm Ordnance Survey Ireland http://maps.osi.ie/publicviewer/#V1,603972,792800,6,4 Accessed 01/11/2012, 6.28pm

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Sites and Monuments Record Database http://webgis.archaeology.ie/NationalMonuments/FlexViewer/ Accessed June/July 2012