Glendalough is one of Ireland’s most iconic landscapes, combining stunning scenery with evocative ruined architecture, including distinctively Irish styles such as the round tower. The popular understanding of the valley’s history is that Saint Kevin retreated into the
wilderness where he could be closer to God, and that there he founded his monastery which rose to a position of pre-dominance before subsequent decline. This is a powerful story, appealing to important myths about the nature of early Irish Christianity and with a complex
relationship with Irish cultural nationalism. However, it is only a partial understanding of the long-term history of how humans have settled the spectacular valley of Glendalough. Glendalough is also often viewed as a natural landscape, but its form is an outcome of
the long-term interaction between people and their environment. This brief outline, and fieldtrip, offers a more holistic perspective on this remarkable landscape.
Ironically, despite its iconic status, comparatively little recent archaeological fieldwork has taken place in Glendalough: this has led to key deficits in terms of basic information about the evolution of the landscape, with subsequent effects in terms of decisions about how
best to manage its cultural heritage. Since 2009 a UCD School of Archaeology teaching and research project has made significant contributions to our knowledge of the valley, and this work forms an important basis for the review offered here.
Our focus is the area surrounding and above the junction of the Glenealo and Glendasan rivers (Figs. 1, 2 & 3). This includes three main archaeological complexes, with other sites found throughout the area. Moving up valley the three main areas are: the main monastic
complex and graveyard; the eastern end of the upper lake; and finally the mining complex at the western end of the valley.
Little is known about the prehistoric settlement of Glendalough although recent work at least demonstrates that prehistoric communities were present in the area. Excavations have recovered small amounts of prehistoric artefacts, but all in derived contexts. These include Neolithic/ Bronze Age stone tools from Temple na Skellig; possible early Neolithic carinated bowl pottery from a residual context on the lawns by the Upper Lake (Fig.4) and Neolithic/Bronze Age stone tools from adjacent to the main monastic complex. The presence of Neolithic material is in keeping with Mitchell’s identification of an opening of the woodlands following 5400 cal. BP (Mitchell and Maldonado-Ruiz 2018).
Saint Kevin and the Early Medieval Monastery
The story of the origins of Glendalough is tied to the figure of Saint Kevin, or Cóemgen. Kevin, who is supposed to have died in 618 or 622 at the venerable (and not wholly convincing) age of 120, is known to us through three Saints Lives, all composed a long time after his death. Kevin is said to have been told by an angel to retreat into solitude and prayer in Glendalough. Initially he spent his time in isolation at the shores of the Upper Lake, but after seven years he founded what we now see as the main monastic complex at the eastern end of the Lower Lake. This is likely to have taken place in the late sixth / early
seventh century. The Lives of Kevin tell many wonderful stories about the Saint, many of which emphasise his relationship with the natural world; such as the claim that he stood still in prayer for so long that a blackbird built a nest in his hand, and hatched her young. The usual historical narrative is that the monastery Kevin founded grew in importance, especially as a focus for pilgrimage. According to one of the later Lives Kevin is supposed to have bought back earth from Rome when visiting the Pope, and to undertake pilgrimage to
Glendalough seven times was considered equivalent to visiting Rome. The importance (and wealth) of the monastery is indicated by it being targeted by Viking raids in 836 Viking, where the destruction of the dertrach (lit. oak house, probably meaning timber church) is noted in the Annals. Until recently, little archaeological evidence was available for these early periods, not least because of the use of timber not stone buildings. Beyond a few early medieval cross slabs and much conjecture, the early phases of the monastic complex were poorly understood beyond the historical references (Etchingham 2011). Our excavations
make an important contribution in this regard.
Monasteries were not simply places of contemplation, but also centres of political and economic power. As Glendalough grew in significance its history became entangled in broader political trends and conflicts: often violent, and involving Viking, Irish and Norman
groups. Through the late tenth and eleventh century it was repeatedly attacked by Viking and Irish raiders, with several records of the area being burnt. By the later eleventh century, Glendalough was being promoted by Muirchertach Ua Briain, High King of Munster, as a rival
to the ambitions of Dublin. In 1111 Dublin was subsumed into the Diocese of Glendalough. Many of the ecclesiastical buildings in the valley date to this period – the height of its power and influence in the late eleventh and twelfth centuries. However, by the middle and later
twelfth century Glendalough’s influence declined as Munster’s influence waned: Glendalough was burned again in 1163. In c. 1214 the Archbishop or Tuam reported that “although anciently held in great veneration … became waste and desolate, and has been so for years past, instead of a church it became a den of thieves and a nest of robbers,
occasioned by its being a vast and solitary desert”. By 1216 it was incorporated into the Diocese of Dublin.
The Main Monastic Complex
The main monastic complex, east of the lower lake, and surrounding the iconic round tower, today comprises the conserved ruins of churches and associated buildings, set in a graveyard.
The complex sits on top of a lateral moraine, bounded to the north and south by the Glendasan and Glenealo streams, and to the east by their junction. It was important that Early Medieval monastic enclosures were enclosed, not simply for defence – but as ways of defining sacred space. The Gatehouse is a unique and marks the formal entrance
to the complex, although the steps are a recent addition. Most of the buildings date to the late eleventh and twelfth century height of Glendalough’s influence and many of them have complex histories. One of the most interesting is the Cathedral which was probably
built c. AD 1100 as Glendalough became the seat of a bishopric. The walls of the cathedral include distinctive stones reused from an earlier stone church, which appears to have been entirely removed and rebuilt. The projecting antae are narrower than the walls of the cathedral and relate to this earlier building, whilst other features such as its western doorway, were modified. Later, c. 1200, a chancel and sacristy were added to the building (Manning 2016; Corlett 2017).
The iconic round tower probably dates to c. AD 1100 AD. The roof
was reconstructed in 1876.
The graveyard, which is still in active use for burial, contains examples of reused early medieval cross marked grave slabs. The graveyard contains over 2000 grave markers and a community group, working in collaboration with UCD School of Archaeology and Historic
Graves (Fig. 5), have surveyed all of these, recording inscriptions and details on an on-line database (https://historicgraves.com/graveyard/glendalough/wi-glda) and in local guides and publications.
The earliest graves are east of the Priest’s House, where plain slabs are probably Eleventh Century in date. Many of the most remarkable grave markers however, date to the eighteenth century. The earliest commemorates Murlagh Doyle and dates to 1697. These are best understood as public works of art, and some make explicit political points about landlords and national identity.
There are a variety of smaller and satellite churches. One of the most important is known as Our Lady’s or St Mary’s. As the name suggests, this church has strong female associations and it may have been a nunnery. The church probably dates to c. 1100, and, like the Cathedral may also incorporate stone from an earlier building. Again, the chancel is a later addition at c. 1200. It is possible that the church should be linked to Derborgaill, who was the mother of Muiterach Ua Briain, and who died in Glendalough in 1098. Either she initiated the building or it was constructed in her memory (Manning 2016; Corlett 2017).
Recent and ongoing excavations have taken place by UCD School of Archaeology immediately west of the main monastic complex (Fig. 6) and between it and St Mary’s (Seaver et al. 2018; Seaver et al. 2017; Seaver et al. 2016; Warren et al. 2015; Seaver et al. 2014). These have been very important in helping understand the evolution of the main
monastic complex. Several features are important.
The excavations may have identified an early enclosure ditch running to the west of the main complex and separating it from the nunnery (Fig.7). A recently obtained radiocarbon date from a charcoal spread low in a c. 8m wide ditch (which is still not fully excavated) suggest that the ditch was open in c. AD 674–772. This could perhaps be an original enclosure feature.
The ditch clearly marks two very different spaces: the area to the west, or ‘outside’ has very few archaeological features, whilst the area on the inside is a dense complex of inter-cutting features. These include post holes with carefully placed packing stones, indicating that
the posts were squared off timbers of c. 30cm width. It has not yet been possible to understand a building plan of these very large posts, but radiocarbon evidence suggests a possible eighth or ninth century date. Large pits, possibly for storage or the disposal of rubbish, date to the eleventh century.
A range of high-status artefacts including a silver coin, ring pin and a fine gilt chip-carved mount from a high-status, ninth-century horse harness (Fig. 8), have been found in this area, and they show the wealth and influence of Glendalough in the eighth, ninth and tenth
centuries. One of our most remarkable finds is a small twelfth century cross made of jet with a tin inlay (Fig. 9). This was originally manufactured in Whitby, North Yorkshire, and they are known from northern Britain, Ireland, Norway and Greenland. Our example is only the fifth found in Ireland.
Our excavations have also shown that the enclosure ditch was extensively remodelled in the twelfth century. Stone lined channels were placed in the ditch, seemingly to channel water from the Glendasan stream to the north to a mill which we hypothesise lies immediately south of our trench. Monasteries often acted as centres for agricultural production, and controlling the mill may have been a way of extracting a tithe. We are still resolving the complex sequence of events associated with these channels, which we think probably date to the late twelfth century and include reusing a broken mill stone as part of the channels (Fig. 10).
Historical sources record that in 1177 “A mighty outbreak of water, for greatness resembling a mountain, went through the midst of Glendalough, carried away the bridge and mill of the town and left some of its fish amid the town. Then it entered Inbhear Mór (Arklow), drowned the fisherman, and swept his net into the sea” (Annals of Tigernach). It is hard to see how a flood could have destroyed a mill at this height above the rivers, but a relocation might have been caused by this natural disaster. The mill channels contain twelfth and thirteenth century ceramics from Dublin, Bristol and Wiltshire, and the channels appear to have gone out of use in the thirteenth century, which would be contemporary with the decline of Glendalough recorded in many of the sources.
Our excavations have also highlighted other aspects of this decline. A cereal drying kiln was placed at the inner edge of the ditch in the late fifteenth century, indicating local agricultural production at a time when Dublin merchants were sanctioned against grain sales to Glendalough. Ceramics, included Portuguese Merida wares, suggest that pilgrimage remained important.
The Upper Lake
The Upper Lake is closely associated with the story of Kevin’s retreat into the wilderness. The carefully manicured lawns immediately east of the Upper Lake which now attract enormous numbers of visitors were formerly known as Kevin’s Desert (Disert Chaoimhghin)
– meaning that it was a wilderness and place for the classic early Christian retreat into nature. Reality is slightly more complicated.
Until recently, there was little good archaeological evidence for early activity at the Upper Lake. Some simple mica schist crosses and cross slabs are likely early medieval, and certainly predate the eleventh and twelfth century stone churches in the area (Harney 2011), but there was nothing that could be associated with the supposed period of
Recent excavations at the ‘caher’ near the Upper Lake have changed this (Fig.11). The ‘caher’ is a very enigmatic monument – a circular stone and earth wall c. 20m in diameter with one entrance, with some similarities to early medieval stone forts. The modern appearance of the caher is very unusual, mainly the product of extensive rebuilding in the mid-twentieth century, meaning that it has been very hard to classify this monument.
Excavations by UCD School of Archaeology have demonstrated that the modern rebuild sits on top of a series of phases of early medieval enclosures, including ditches and stone banks (Fig. 12). The earliest ditch is a substantial feature with a classic ‘ankle breaker’ slot at the bottom – a defensive feature (Fig.13). The lower levels of the ditch contain significant quantities of iron slag, industrial waste from the production of iron objects. We have radiocarbon dated this early activity to c. AD 428–593, and the ditch appears to have filled by the ninth century, at which time it was a stone structure. The early date for the ditch means that this classic early medieval enclosure, with associated industrial activity and defensive characteristics is likely contemporary with the time that Kevin is supposed to have retreated into the wilderness here.
There are further hints of early activity in the name of the church at Reefert. The church itself probably dates to c. AD 1100 and, as with many other churches in Glendalough, shows signs of having recycled an earlier stone church. The place name derives from the Irish ríogh fheart, which means royal cemetery. Fheart often means a burial ground predating the arrival of Christianity in the fifth century and it is possible that this was an existing burial ground of some status which was later Christianised. Again, there is not an easy fit with the legend of a retreat into the wilderness.
The isolated church of Temple-na-Skellig lies on the southern shore of the Upper Lake in a remote and difficult to access location (Fig. 14). The church dates to the twelfth century. Excavations were undertaken here by Françoise Henry in the 1950s with a team of local
workmen. These recovered evidence of early medieval buildings on an artificial terrace immediately west of the church. We have been preparing these excavations for final publication. This has allowed us to date some of these buildings to the twelfth to thirteenth centuries, with a possible earlier ninth-century date for other activity. A porphyry tile fragment found at Temple-na-Skellig originated in a building from the Roman Empire. It most likely formed part of either a portable altar or a token. Immediately east of Temple-na-Skellig, the difficult to access St Kevin’s Bed is either a wholly artificial or modified cave in a vertical wall above the lake. It likely formed a penitential or retreat cell.
Few people realise that the most numerous single type of archaeological site in Glendalough is not related to religious activity at all, but is the much more mundane evidence of an industrial history which transformed the Glendalough landscape. Over 100 charcoal production platforms are recorded around the Upper Lake (Fig. 14), mainly now located in woodland. These sites are platforms cut into the hill slopes, providing a flat surface on which wood could be stacked, covered and then fired.
Recent excavations of these sites have provided clarity on their age and how the people who constructed them exploited the woodland (McDermott et al. 2012; Warren et al. 2012) (Fig. 15). Radiocarbon dates demonstrate that they most likely date to c. cal. AD 1650–1730. Analysis of the charcoal recovered from excavations (Fig. 16) shows that a mixture of species was exploited, mainly oak, birch and holly, with trunks and smaller branches used.
The charcoal production industry in Ireland was linked to the expansion of iron working at this time. In some areas of Britain charcoal production was (relatively) well managed, with coppiced oak providing the majority of the fuel. In Ireland however, its early phases, following c. cal. AD 1670, this was often not the case, and woodlands were entirely removed to fuel the iron works. This was an extractive, colonial exploitation of Irish resources. This context is very much in keeping with the dates and charcoal evidence from our excavations.
Indeed, many early images of Glendalough show it as a treeless landscape, for example Sandy’s view of the Seven Churches in Glendalough, engraved in 1778. These are views of a post-industrial landscape, a product of colonialism. An open landscape is also indicated
in pollen records (Mitchell and Maldonado-Ruiz 2018). The trees that now line the Upper Lake are either plantations associated with the lead mines (on the northern shores), semi-natural regrowth (the southern shores) or recent forestry plantations.
The extent of deforestation seems likely to have led to significant impacts on erosion and run-off, but this has not been documented.
As well as the charcoal production, the Glendalough landscape was transformed by another major industrial process – lead mining (Fig. 14; Critchley 2007; Cowan 2007). Lead was first identified in the early nineteenth century, and exploited from 1825, initially by the Mining Company of Ireland. This was a major industry, employing c. 200 men in the 1850s and producing 120 tons of lead ore per month. Much of the early twentieth century activity focused on reworking older spoil, but a second phase of deep excavation took place from
1948–1957. Some miners are still alive today and a series of welcome initiatives have been promoting the mining heritage of the area.
The remains of this mining activity dominate the western end of the Glendalough Valley and are also found in neighbouring valleys. They are amongst Ireland’s most important industrial archaeological landscapes. Infrastructure for the mines transformed the landscape – the popular walk along the north shore of the Upper Lake follows the miners road, and the remains of miner’s cottages are found along it. The miners planted a million trees in the mid-nineteenth century alone, mainly to use as pit props but also as a commercial crop.
The impacts of tourism
Finally, the Glendalough landscape has been transformed since the nineteenth century through agriculture, forestry and tourism. The rediscovery of Glendalough in the nineteenth century was tied in complex ways to ideals of nature, Irish nationalism and the development
of Dublin, but the tourist industry was transformative (Ní Cheallaigh 2011). Many sites were heavily reconstructed at this time – in one instance, miners were employed to reconstruct Reefert Church. A tourist infrastructure was also out in place – with a two storey hotel built at the Upper Lake (Fig. 17); and many business opportunities established including boat trips to Temple-na-Skellig and Kevin’s Bed.
The impacts of these processes of transformation are highlighted clearly at the Upper Lake. Here nineteenth century accounts highlight the ongoing destruction of archaeological sites by agriculture. Our excavations of one of the stone cairn cross bases in this area recovered a
fragment of a mid-twentieth century pint glass from under the middle of the cairn (Fig. 18), suggesting that although the cross itself may be of antiquity, its current setting, and possibly location, are a result of people trying to create the right kind of landscape.
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Fig. 1: Image courtesy of Anthony Corns and the Discovery Programme
Fig. 2: Image courtesy of the Discovery Programme
Fig. 3: Image courtesy of Rob Sands, UCD School of Archaeology
Fig. 12: Image courtesy of Seamus Ó Murchú
Fig. 17: Image courtesy of the National Library of Ireland
All other images courtesy of UCD School of Archaeology
Article kindly reproduced with the permission of the authors.