Enjoy this article written by Kimberley Teale of Dig Ventures


In Autumn 2021, DigVentures conducted a geophysical survey in the field surrounding St Mary’s Abbey as part of the ‘Rediscovering Ancient Connections’ project. The survey, comprising Ground Penetrating Radar (GPR), under License No. 21R0196, aimed to clarify some previously conjectured monastic features within the grounds as well as explore an area around the remains of a previously discovered probable watermill.

Geophysical Survey at medieval ferns on a sunny day

Image 1 – Undertaking GPR in the grounds of St Marys

The site had been previously studied using the geophysical techniques of magnetometry and earth resistance in 2015 (Bhreathnach and Dowling 2021), which discovered significant evidence relating to an early monastic site at Ferns, including the eastern limits of the monastic enclosure and anomalies suggestive of structures (and ancillary features) of different periods. Archaeological excavations then followed by TVAS archaeology in 2019/2020, and later by the IAFS from 2021 to present. These excavations confirmed the presence of an inner and outer enclosures, as well as other medieval structures including, in the case of TVAS’ excavation, the partial remains of a horizontal watermill.

And so, on a bright and sunny October day, under the watchful eye of a herd of young cattle, a GPR survey was undertaken on two areas within the grounds: an area immediately south and east of St Mary’s Abbey and an area in the very north-east of St Mary’s Field, close to the remains of the watermill discovered by TVAS.

Image 2 – Setting up the GPR survey transects under the watchful eye of the local herd

The GPR data next to St Mary’s Abbey revealed various rectilinear high-amplitude anomalies which have been interpreted as building foundations, as well as low-amplitude anomalies which are suggestive of foundations having been removed leaving ‘robber trenches’ behind.

Image 3 – GPR Depth Slice 4 (0.74 – 0.98m) and interpretation close to St Mary’s Abbey

In the image above, a possible enclosure F1 can be seen in the north-east of the data, with smaller internal divisions. When compared with Bhreathnach and Dowling’s data, the location seems to correlate with the location of a possible ditch relating to land divisions.

To the south of St Mary’s Abbey, linear high-amplitude anomalies F2 running east-west and north-south are suggestive of stone building foundations. These anomalies correspond with Bhreathnach and Dowling’s findings, who suggested their anomalies could be related to the remains of a c. twelfth-century cloister. This interpretation was further supported by an earth resistance survey, which confirmed the presence of a high resistance rectangular feature amongst an area of increased resistance, suggestive of buried stone features surrounded by building collapse and rubble*.

The GPR data collected in the north of St Mary’s Field identified features which could relate to the site of the sixth century St Maodhóg’s / Saint Mogue’s, otherwise known as Saint Aidan’s early church (WX015-003002-).

Image 4 – GPR Depth Slice 5 (1.00 – 1.26 m) and interpretation, close the site of the watermill

Broad linear high-amplitude ditch-like anomalies F16 identified in the data again correlate with Bhreathnach and Dowling’s findings, which are said to relate to the possible eastern boundary of an early church pre-dating St Mary’s Abbey. The square anomaly in the centre of them, F17, could also relate to this early church. Excavations by TVAS in 2020 in this broader area revealed ditches consistent with the outer ecclesiastical enclosures and also revealed the medieval watermill, with wooden remains including a wheel pit. It is quite possible that this square feature found during our surveys could relate to the former watermill.

With IAFS continuing excavations in 2023, it is hoped that more light will be shed on these exciting discoveries and the medieval origins hidden in St Mary’s Field (see also Blog Four).

* These findings have since been further assessed by a major research excavation at the site by the IAFS, which remains ongoing at the time of writing.


Further Reading:

Bhreathnach, E. and Dowling, G. 2021 ‘Forming an episcopal see and an Augustinian foundation in medieval Ireland: the case of Ferns, Co. Wexford’, Proceedings of the Royal Irish Academy 121C, 191–226.

Acknowledgment of Support

This blog is number nine of a ten-part series entitled ‘Discovering Medieval Ferns’ which has been funded by the ‘Rediscovering Ancient Connections – The Saints (Ancient Connections)’ Project.

Ancient Connections Logo for Discovering Medieval Ferns blog series

Ancient Connections’ is an ‘inter-reg’ cross-border arts and heritage project linking Pembrokeshire and north Wexford, which strives to revive the ancient links between these communities, allowing them to rediscover their shared heritage and trade knowledge, experience, and skills.

‘Ancient Connections’ have also funded a major academic volume, also entitled ‘Discovering Medieval Ferns, upon which this blog series is based.

Discovering Medieval Ferns Book Cover 2023

This volume, which includes fifteen papers from an interdisciplinary team of twenty+ scholars, aims to highlight the remarkable history and archaeology of medieval Ferns, focusing on intriguing discoveries from recent excavations and research programmes.

The volume, which is the most complete picture to date of the origins and evolution of medieval Ferns, will be published by Four Courts Press later in 2023.

The logos of EU and Welsh bodies involved with Ancient Connections that have supported the excavation at St Mary's