2024:226 - Glendalough, Sevenchurches or Camaderry Townland, Wicklow

Excavations at Glendalough (Sevenchurches or Camaderry townland) by University College Dublin School of Archaeology 2017-2023.
David O’Reilly July 2024

This report is supplementary to the previously submitted report covering the years 2014-2016 at Glendalough, Co. Wicklow conducted by UCD school of Archaeology (2016:486 - Seven Churches, Glendalough, Wicklow). Excavations between 2017 to 2023 continued to focus on Trench 11 where the main monastic enclosure ditch had been identified by geophysical survey. Three new smaller trenches were also opened to test further geophysical anomalies. These were: Trench 13 to the south of Trench 11 (2019); Trench 14 north of Trench 11 (2021); and Trench 15 north-west of Trench 11 (2022-2023). No excavations took place in 2020 due to Covid 19.

Trench 11
In Trench 11 (25m x 8m) the excavations revealed that the large ditch had gone through several phases of remodelling and reuse. It was initially constructed in the early medieval period as a monastic vallum enclosing the core of the monastic complex. At an early date the outer and inner (western and eastern) faces of the ditch were lined with substantial dry-stone revetment walls built of large granite blocks and boulders and flat schist slabs. Two radiocarbon dates were obtained from early contexts in this ditch: Betula charcoal from the basal fill returned a date of 661-774 AD (UBA-43256) and Corylus Avellana from an early charcoal spread abutting the western revetment wall returned a date of 674-772AD (UBA-39634).
The ditch was allowed to silt up over time and several layers of thin, silty sediments survived abutting the eastern ditch revetment. The remainder of these thin early layers were removed, and the ditch appears to have been partially cleared out to make way for a series of north-south revetment walls inserted within the line of the ditch. These walls gradually narrowed the ditch until a single 1m wide channel was left at the western side. Finds of medieval pottery spanning the 12th to 14th centuries are associated with this phase of reworking of the monastic enclosure ditch. It is proposed that this 1m wide channel was part of a millrace constructed by channelling water some 200m from the Glendasan River to the north of the monastery into the enclosure ditch and out again into the Glenealo River, at least 100m to the south. This theory is supported by finds of a number of very large granite millstone fragments built into the revetment walls in Trench 11, indicating the presence of a mill building nearby.
Excavations at the eastern end of Trench 11, in the area enclosed by the monastic enclosure ditch, uncovered intense activity with numerous pits, spreads and and some substantial stone-lined post-holes. Two radiocarbon dates were obtained from post-holes immediately inside the enclosure ditch. One Corylus avellana charcoal fragment dated to 651-866AD (UBA-30034) and one Corylus avellana hazelnut shell dated to 725-961AD (UBA-34832). One large pit in the same area returned a date of 1027-1156AD (UBA-34831) from a grain of Avena Sp. Later activity is attested by a grain of Triticum Sp. from the charred fill of a cereal-drying kiln located on the inner edge of the silted-up ditch which returned a date of 1415-1493AD (UBA-34833).

The intensive activity inside the enclosure was in stark contrast to the western end of Trench 11 located outside the enclosure ditch where no substantial features were uncovered. The geophysical survey had suggested a possible rectangular building in this area, but no such remains were found.

Trench 13
Trench 13 (10m x 2m) was opened in 2019 and was located 30m south of Trench 11. Geophysical survey indicated that the early medieval ditch continued to run down the slope south towards the Glenealo River. It had also highlighted an area of high magnetic resistance immediately west of the ditch on a raised knoll. The same area also showed up on aerial photographs as a patch of parched grass measuring approximately 20m east-west by 30m. It was proposed that the area of high resistivity could represent the remains of a stone structure built beside the ditch, possibly a mill building. Trench 13 was designed to cut across part of the elevated area of high resistivity to determine if a mill building was located here, and also across part of the linear feature. This would hopefully confirm that the linear feature was indeed a continuation of the early medieval ditch and whether the revetment walls seen in Trench 11 continued.
At the western end of the trench the ploughsoil layer covered a deposit of compact glacial moraine gravel. This compact natural deposit is the likely cause of the parched soil visible in the aerial photographs and also the cause of the area of high resistance detected in the geophysical survey. No trace of a structure of any kind was found in this area.
At the eastern end of the trench the ploughsoil overlay dark, silty sand with frequent inclusions of larger stones, a sondage near the end the trench uncovered the upper course of a probable revetment wall lining the western edge of a ditch, mirroring the layout of the ditch and revetment in Trench 11. Time constraints meant that these features was not excavated further, and the trench was subsequently backfilled.
The excavation of Trench 13 proved convincingly that the ditch uncovered in Trench 11 does indeed run southwards as indicated by the geophysical survey. It also seems that the western revetment wall of the final phase mill channel is also present in the eastern edge of Trench 13. The excavation proved that there was no trace of a structure on the patch of elevated ground to the west of the ditch. A full understanding of the relationship of the ditch in Trench 13 to the structures in Trench 11 will depend on how each are positioned in relation to the posited mill structure that has yet to be identified.

Trench 14
Trench 14 was opened in 2021. It was located 20m to the north of Trench 11 and was positioned to investigate a north-south aligned linear feature visible as a positively magnetic anomaly on the geophysical survey. It was suspected that this was a headrace contiguous with one of the millrace channels identified in Trench 11.
Excavations in the 10m x 3m trench showed that the linear feature identified in the geophysical survey was clearly visible running on a north-south alignment through the centre of the trench. Two parallel revetment walls were identified defining the eastern and western edges of the channel. Once this feature had been identified a 5m x 2m extension was extended southwards. The channel and the revetment walls could be traced running north-south across the full 5m width of the trench. A sondage was cut into the channel 1m south of the northern edge of the trench showing a clear sequence of construction closely comparable to that seen in the final phase millrace channel in Trench 11 although the base was not exposed.
The excavations in Trench 14 confirmed that the north-south aligned linear feature seen in the geophysical survey was indeed present and was very similar in character and construction to the late phase millrace channel seen in Trench 11. This feature is likely to be part of the headrace that conducted water from the Glendasan River southwards into the reworked large monastic enclosure ditch uncovered in Trench 11. The finds of medieval pottery from these deposits spanning the 12th to 14th centuries are of the same types and date range as the pottery recovered from the upper ditch fills in Trench 11.

Trench 15
Trench 15 was L-shaped (10m x 10m) located 42m north-west of Trench 11 and excavated in 2022-2023. The geophysical survey of this area had highlighted a possible circular feature approximately 13m in diameter with a pit-like feature at its centre. The survey also showed a linear feature on a roughly north-south alignment running parallel to the millrace excavated in Trench 14 and running through the circular feature. This circular feature was provisionally interpreted as a prehistoric ring-ditch with a possible central burial pit. Trench 15 was intended to explore this possible prehistoric ring-ditch with a view to gaining a better understanding of the prehistoric presence in the area.
Excavation uncovered a group of three very large, deep, pits and two hearths as well as a scattering of stake-holes and small post-holes, furrows and one north-south aligned linear feature. No trace of a circular prehistoric feature was found.
The three large pits are of a scale and character not seen before in the UCD excavations. These pits are very large, up to 2.6m in diameter, and up to 1.1m in depth below ploughsoil with multiple layers of stratigraphy visible in the excavated section faces. All of the pits produced very large quantities of metallurgical waste. The pits are located to the west of the large ditch seen in Trench 11 and are therefore outside of the monastic enclosure, suggesting a separation of industrial activity from the main core of the monastery, a pattern that is often seen on other monastic sites.
The north-south linear feature is of uncertain date, it was heavily disturbed by post-medieval plough furrows and contained no diagnostic artefacts. The feature is visible running on a roughly north-south alignment but is not completely straight, having several slight curves throughout its course. The feature seems to respect the general alignment of the medieval mill channel excavated in Trench 14 suggesting that it may be broadly contemporary with it.

Finds Assemblage
Due to the free-draining and acidic soils at Glendalough none of the organic material usually uncovered at large early medieval or medieval sites has survived, the finds assemblage contains no bone, leather, antler, textile or wooden artefacts.
The artefact assemblage from the excavations includes a small number of prehistoric finds including a saddle quern, flint tools and flint debitage as well as two possible petit tranchet derivative arrowhead fragments, one biconical jet-like bead, and two fragments of late Neolithic pottery, all from the overlying topsoil layer or in disturbed contexts within 19th-century cultivation and furrows.
A small but significant assemblage of early medieval material has been recovered including a silver penny of King Sitric of Dublin, glass beads and cabochons, a small copper-alloy harness mount with gilded chip-carved interlace, several copper-alloy ring pin fragments and one complete polyhedral crutch-headed ring pin with close parallels with examples from Hiberno-Norse Dublin. Other medieval finds include several large granite millstone fragments, whetstones, grinding stones, bullaun stones, loom weights, glass beads and one tiny cross made of Whitby jet.
The excavations have produced a large assemblage of medieval pottery most of which spans the 12th to 14th centuries. This assemblage is predominantly comprised of locally made Leinster cooking wares and Dublin-type wares with occasional imports of English Ham Green and Minety Ware, as well as occasional French Saintonge sherds and possible Merida ware from the Iberian Peninsula.
On-site medieval iron working is attested by a tuyere fragment and by large volumes of metallurgical waste found in the upper layers of the enclosure ditch in Trench 11 and in the very large pits in Trench 15. A large number of very corroded iron artefacts have also been recovered, some of which may have been made on site. These include iron knives, nails, horseshoe fragments, belt buckle fragments and one iron rowel spur. Most of the iron finds are very heavily corroded and fragmented and are therefore unidentifiable. All bone recovered is burnt and fragmentary and none was identifiable as artefactual.
A large percentage of the artefacts recovered during the excavations are of post-medieval pottery and glass sherds from the topsoil/ploughsoil layers identified as fragments of cups, plates, jugs, basins, drinking glasses, whiskey jars, dairy crocks as well as numerous fragments of clay tobacco pipes.

University College Dublin, Belfield, Dublin 4.