A Lost Treasure Rediscovered: The Ardshanbally Brooch-Pin

By Mara Tesorieri, Susannah Kelly, and John Channing

Illustration 1: The Ardshanbally Brooch-pin following conservation (Photo: John Channing, AMS)
Illustration 1: The Ardshanbally Brooch-pin following conservation (Photo: John Channing, AMS).

On Thursday July 25th, 2024 archaeologist Jimmy Dobson, was excavating a section through the fill of a newly identified enclosure ditch, at a site designated Ardshanbally 1 on the route of the Adare Bypass in Co. Limerick, when he uncovered a 1200 year-old bronze brooch-pin. The beautifully decorated object emphasises the status of some of the people living along the Shannon Estuary in early medieval times and their expertise in metalworking. It is one of the best-preserved examples of this type of brooch uncovered during archaeological excavation in Ireland in many decades. The quality of the object has led to its selection by curators at the National Museum of Ireland for inclusion in a major exhibition showcasing Ireland’s early medieval treasures – Words on the Wave.

Since early 2024 archaeologists from Archaeological Management Solutions (AMS) have been carrying out pre-construction archaeological investigations on the route of the Foynes to Limerick Road Project. This 34 km long road scheme, which includes the Adare Bypass, is located to the south of the Shannon Estuary (Illus. 2). The new road passes through a rich historical landscape with a notably dense distribution of early medieval (5th to 12th century AD) ringforts in the rural areas and notable Anglo-Norman towns such as Adare and Askeaton. Great care was taken during the design phase of the project to minimise impacts on known archaeological monuments and historic sites. However, as is the case with every development project, there was the potential for previously undocumented archaeological sites to be uncovered. The pre-construction archaeological excavations carried out by AMS on behalf of Limerick City and County Council (LCCC) and Transport Infrastructure Ireland (TII) were designed to systematically investigate the land acquired for road construction, so that any previously undocumented archaeological sites could be identified and excavated well in advance of construction works starting. These excavations have led to the discovery of over 140 previously unrecorded archaeological sites, revealing evidence of human activity dating from prehistory into the modern period. The Ardshanbally 1 enclosure at which the brooch-pin was found is one of these previously unrecorded sites, however, it is worth noting that the placename, an anglicisation of the Irish Ard an tSeanbhaile meaning ‘the high place of the old homestead’, likely preserves a folk memory of an ancient settlement in this area.

Illustration 2: Foynes to Limerick Road (including Adare Bypass) Scheme and location of Ardshanbally 1 (Figure: Raul Zafra, AMS).
Illustration 2: Foynes to Limerick Road (including Adare Bypass) Scheme and location of Ardshanbally 1 (Figure: Raul Zafra, AMS).

The most substantial archaeological feature uncovered at Ardshanbally 1 was a circular ditched enclosure c.22m in internal diameter. The ditch was partially rock-cut and ranged from 2 m to 3.40 m in width and from 0.88 m to 1.60 m in depth. A segment of a concentric outer ditch was found on its northwest side. No entrance was identified, it must have been located in the unexcavated southern portion of the enclosure. Nor did any evidence for an internal bank survive, it must have been ploughed away since the site was last occupied more than a millennium ago. The only archaeological features that had survived within the enclosed area was a small number of pits and postholes, however, a large amount of animal bone (cattle, pig and sheep) recovered from the enclosure ditch is suggestive of domestic activity within the enclosure. As well as the brooch-pin, several other archaeological objects were recovered during the excavation, including ringed-pins and a decorated antler spindle whorl.

The Ardshanbally 1 enclosure was located at the northern end of a low ridge that overlooks the River Maigue and its floodplain to the west (Illus. 3–5). Another early medieval circular enclosure, Curraghbeg 1, was discovered on the ridge on the opposite side of the river valley. The two sites were intervisible and based on their similar morphology they are likely to have been contemporary, they may have been sited so that their occupants could keep an eye on comings and goings on the river.

Following its careful excavation the brooch-pin was packaged, removed from site and brought to the AMS post-excavation facilities, where it was photographed and measured. The brooch-pin consists of two elements; the circular brooch head (hoop) measuring 4.36cm in diameter and the pin measuring 12.88cm in length. The National Museum of Ireland (NMI) was informed of the discovery and the brooch-pin was delivered to their conservation facilities, where Raghnall Ó Floinn, former Director of the National Museum of Ireland, identified the object as a brooch-pin of ninth century date. Paul Mullarkey (metals conservation and scientific analysis specialist, NMI), carried out X-Ray Fluorescence (XRF) on the brooch-pin and its components to determine the type of metal or metals used in its fabrication. Readings along the front and back of the head and along the pin all provided similar results, indicating the brooch was made of cast bronze (primarily copper, with small levels of lead and tin).

Illustration 3: Archaeological site plan of Ardshanbally 1, showing the find location of the Ardshanbally brooch-pin, as well as other objects including two ringed-pins, a spindle whorl made of antler, and a glass bead (possibly ninth-century in date) (Figure: Raul Zafra, AMS).
Illustration 3: Archaeological site plan of Ardshanbally 1, showing the find location of the Ardshanbally brooch-pin, as well as other objects including two ringed-pins, a spindle whorl made of antler, and a glass bead (possibly ninth-century in date) (Figure: Raul Zafra, AMS).
Illustration 4: Aerial view of Ardshanbally 1 during excavation (north to top) (Photo: John Channing, AMS).
Illustration 4: Aerial view of Ardshanbally 1 during excavation (north to top) (Photo: John Channing, AMS).
Illustration 5: The archaeological team excavating the enclosure ditch, where the brooch-pin was recovered (looking southwest) (Photo: John Channing, AMS).
Illustration 5: The archaeological team excavating the enclosure ditch, where the brooch-pin was recovered (looking southwest) (Photo: John Channing, AMS).

Conservation of the brooch-pin by Susannah Kelly began with an initial assessment and recording of its condition, prior to deciding on what treatments were necessary (Illus. 6). Upon examination under a microscope, two blue glass studs, two amber insets and some textile fibres were identified amongst and below the corrosion. Copper salts are toxic to micro-organisms. As micro-organisms are the prime cause of the destruction of organic materials, any organic material in contact with a bronze object has the potential to survive. Wood, leather and textile remains are therefore quite commonly found in association with such artefacts. In this case a few fibres remained attached to the top of the brooch-pin and are likely associated with the article of clothing that the brooch-pin had been worn on.

The initial cleaning of the brooch-pin took place using swabs of pure alcohol (Industrial Methylated Spirits - IMS) to gently remove any loosely attached soil and corrosion products that covered the glass and amber decorative components (Illus. 7). The amber insets were fragmentary and detaching from the surface. Once cleaned these were consolidated with Paraloid B-72 (a conservation grade acrylic adhesive and consolidant that is fully reversible and removable if required). The glass studs were also coated with Paraloid to protect them during cleaning of the metal areas.

Illustration 6: Conservation Specialist Susannah Kelly assessing the condition of the brooch (Photo: John Channing, AMS).
Illustration 6: Conservation Specialist Susannah Kelly assessing the condition of the brooch (Photo: John Channing, AMS).
Illustration 7: The use of cotton swabs dipped in pure alcohol to help remove soil (Photo: John Channing, AMS).
Illustration 7: The use of cotton swabs dipped in pure alcohol to help remove soil (Photo: John Channing, AMS).

The textile fibres were removed with a pair of fine forceps from the top of the pin after softening the surrounding corrosion products with ethanol. These can then be analysed separately and re-attached when required.

With the other material components protected, it was now safe to clean the metal surfaces. A scalpel, glass bristle brush and IMS swabs were used to remove dense crusts that obscured the metal surface (Illus. 8 and 9). All work was carried out using a binocular microscope. A decorated surface was fully revealed below the corrosion products, and apart from some spots where the surface had been disrupted by bronze disease and blisters, the overall surface was in a fair condition.

Illustration 8: Using a scalpel to help loosen remains of soil (Photo: John Channing, AMS).
Illustration 8: Using a scalpel to help loosen remains of soil (Photo: John Channing, AMS).
Illustration 9: Brushing the loosened soil off using a glass bristle brush (Photo: John Channing, AMS).
Illustration 9: Brushing the loosened soil off using a glass bristle brush (Photo: John Channing, AMS).

Once the surfaces had been cleaned it was necessary to treat the object chemically in order to arrest the bronze disease process. For this, the brooch was de-greased in acetone and immersed under vacuum in a solution of Benzotriazole (BTA) in IMS for 48 hours. It was then thoroughly rinsed to remove a residual BTA and dried to a very low relative humidity for eight hours in a desiccator chamber. When sufficient moisture was removed from the metal it was sealed in Incralac, which is a specially formulated protective coating for bronzes. This protects against moisture ingress which is a factor in the reactivation of the bronze disease corrosion process. The brooch is now safer, more stable and capable of withstanding further study, analysis and display.

Cleaning of the brooch-pin revealed in full the intricate design on the front of the brooch head, consisting of zoomorphic patterns on recessed panels separated by glass studs and amber insets. No decoration is present on the back (Illus. 10 and 11). The zoomorphic designs on the two ‘terminals’ appear to represent beasts biting their own tails (further analysis to confirm). The ‘terminals’ are blocked by a raised lentoid shape 1.6cm in length, perhaps imitating a glass or amber stud, and framed on the outside by two small, curved flourishes (Illus. 11 and 12). Two large blue-glass studs separate the ‘terminal’ panels from the hoop, which complete the circular head. The hoop measures 0.62cm in width, its recessed surface is decorated with raised ribbon interlaced designs. At the top of the decorative ring the hoop ends are joined by a narrow bar, placed between two D-shaped amber insets (Plate 13). The top of the pin was flattened and looped around the narrow bar forming a hinge. The body of the pin is rounded and tapers to a pointed end.

Based on the form and design, the brooch-pin is likely ninth century in date, with other finds recovered from the ditch fill, including a small globular glass bead, also associated with a ninth-century date.

Illustration 10: Back and front of brooch-pin after conservation (Photo: John Channing, AMS)
Illustration 10: Back and front of brooch-pin after conservation (Photo: John Channing, AMS).
Illustration 11: Close-up of front of brooch head showing zoomorphic design and glass insets (Photo: John Channing, AMS).
Illustration 11: Close-up of front of brooch head showing zoomorphic design and glass insets (Photo: John Channing, AMS).
Illustration 12: Close-up of the left terminus showing the recessed panel and raised zoomorphic design bordered at the ‘terminus’ end by a raised lentoid shape and a blue-glass stud at the hoop end, with a bronze flourish along the outside. The red-coloured markings are a result of scarring from cuprous oxide blisters. (Photo: John Channing, AMS).
Illustration 12: Close-up of the left terminus showing the recessed panel and raised zoomorphic design bordered at the ‘terminus’ end by a raised lentoid shape and a blue-glass stud at the hoop end, with a bronze flourish along the outside. The red-coloured markings are a result of scarring from cuprous oxide blisters (Photo: John Channing, AMS).

The brooch-pin is currently being drawn by the AMS illustrator Elaine Lynch, prior to going on display in the Words on the Wave exhibition. Following the exhibition the artefact will undergo full analysis by early medieval decorative art and iconography specialist, Conor Newman, Senior Lecturer at the University of Galway. The other finds from Ardshanbally 1, including the fibres recovered from the brooch-pin, the ringed-pins, spindle whorl, glass bead as well as the animal bone, charcoal and charred plant remains, will also be analysed by the appropriate specialists who will be able to provide us with detailed descriptions and comparisons to similar finds from Ireland and further afield. This information, along with the excavation records and radiocarbon dating programme, which is currently underway, will help to provide a detailed understanding of life at Ardshanbally during the early medieval period and will hopefully shed light on why this exceptional piece of aristocratic jewellery ended up being buried in the enclosure ditch.

Further Information

For updates on the progress of the pre-construction archaeological investigations along the Foynes to Limerick Road and on-going post-excavation analysis follow the AMS social media accounts (Facebook, Instagram, Youtube, and Linkedin, as well as checking-in on the AMS website.

To see the brooch in person, don’t miss the exciting new exhibition ‘Words on the Wave: Ireland and St. Gallen in Early Medieval Europe’ at the National Museum of Ireland from May 30th to October 25th, 2025. Further information can be found on the Museum’s website.