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The Elusive Iron Age:

a rare and exciting site type is uncovered at Lismullin, Co. Meath

Archaeologists cleaning the outer enclosure stake-holes in preparation for preliminary drawing. (Mary Deevy)

Aidan O’Connell, excavation director with Archaeological Consultancy Services Ltd, reports on the excavation of a unique post enclosure at Lismullin, Co. Meath, which was recently declared a National Monument.

Archaeological excavations in advance of the Dunshaughlin–Navan section of the M3 Clonee–North of Kells motorway scheme have revealed the presence of a large, postbuilt ceremonial enclosure dating to the early Iron Age (sixth to fourth century BC) in the townland of Lismullin. The post enclosure has been declared a National Monument and the Minister of the Environment, Heritage and Local Government, in consultation with the National Museum of Ireland (NMI), has issued ministerial directions pertaining to its full excavation within the road corridor.

A committee of experts—comprising representatives from the National Monuments Service of the Department of Environment, Heritage and Local Government, the NMI, the Department of Archaeology NUI Galway, the School of Archaeology UCD and the NRA—has been set up to advise on the excavations, and a range of techniques, including geophysical surveys and geoarchaeological studies, are being employed in tandem with the excavations to ensure that the maximum amount of information is obtained. Full archaeological excavation of the site within the road corridor was ongoing at the time of writing and was expected to be completed by early November 2007.

The site

Lismullin 1 is located 850 m to the north-east of the existing N3, about halfway between Navan and Dunshaughlin. It is 2.1 km northeast of the Hill of Tara and bounded to the north-west by the River Gabhra. The total area under investigation covers 27,360 m2. In addition to the enclosure, a range of features dating to the Early–Middle Neolithic, the final Neolithic/Early Bronze Age, the later Bronze Age, the medieval period and the post-medieval/early modern period have been identified (see Prehistoric Ritual and Early Medieval Land Use panels).

Iron Age ceremonial enclosure

The post enclosure occupies a natural, saucer-shaped depression at the west of the site, surrounded on all sides by a ridge of higher ground. Both the enclosure and this high ridge extend beyond the south-western site boundary. There are three surviving enclosure elements: an outer enclosure, 80 m in diameter, defined by a concentric double ring of post-holes; a central inner enclosure, defined by a single ring of closely spaced post-holes; and an east-facing entrance comprised of an avenue of widely spaced post-holes.

The two outer enclosing rings are 1.5–2 m apart and the individual post-holes are arranged at 0.4–1 m intervals (averaging 0.6 m). The excavated post-holes from the outer enclosure average 0.21 m in diameter and 0.2 m in depth, but range from smaller examples less than 0.15 m in diameter to larger post-holes that are up to 0.29 m wide. Charcoal from post-pipes (the voids left once the posts have rotted away) associated with two of the post-holes has been radiocarbondated to 520–380 BC and 490–370 BC, placing the enclosure firmly within an early Iron Age context.

click above for larger plan

The enclosure entrance is located at the east and is defined by a gap in the (outer) double ring, with a slightly funnel-shaped avenue of post-holes narrowing towards the inner circle. At a point about 4 m from the inner circle a slot-trench traverses the avenue. This may have supported a screen that would have restricted the view from the entranceway into the inner enclosure. The inner ring has a diameter of 16 m and a number of internal features, including three possible pits that appear to have charcoal-rich upper fills and are oriented towards the eastern entrance.

There are additional clusters of postholes, stake-holes and pits located between the inner and outer enclosure elements, but no clear patterns have been identified. A range of artefacts has been recovered from the enclosed area, including a fragment of a rectangular stone chisel or adze—which came from the subsoil surface within the northern area of the enclosure—Middle Bronze Age domestic pottery collected from a pit between the two outer rings and numerous sherds of later Bronze Age coarse ware pottery from four pits on the enclosure interior.

The Lismullin enclosure appears to represent a single phase of construction and a relatively short period of use. It seems that the rings of posts were freestanding as there is no indication of a slot-trench between them to support a timber or wattle facing. In addition, the use of large numbers of relatively small posts and their close spacing suggests there would have been little need to additionally define the enclosed area or its circular manifestation.

Geoarchaeologist Steve Lancaster, Headland Archaeology Ltd, examining the soil profile at Lismullin with one of the site supervisors. (Maria FitzGerald) Pre-excavation plan overlaid with an interpretive drawing of the results of a caesium magnetometer survey (blue and red circles and lines) and a magnetic susceptibility survey of the north-west quadrant. Neither method identified the enclosure features. (Earthsound Archaeological Geophysics) 54


The choice of location is important. The enclosure occupies a discreet, sheltered position with the surrounding higher ground giving the effect of a natural amphitheatre. Recent aerial topographical survey at the site has demonstrated that the enclosure occupies the lowest point in this natural hollow, rather than its exact centre, which suggests that the activities taking place within the enclosure could be viewed from the outside. The purpose of the possible blocking screen (if it is associated with the enclosure) at the end of the entrance-way may have been to restrict the movement and/or view of people from the outer enclosure to the central area. It possibly defined a solid boundary between the area used in the context of congregation and procession (i.e. the east–west-aligned avenue) and the inner ceremonial space. The construction and siting of the Lismullin enclosure suggest that it was custom-built to serve the, possibly shortterm, needs of its builders; a monument tailormade for a particular set of events in a carefully chosen landscape setting.

Ceremonial enclosures elsewhere
Post enclosures form components of a variety of ritual and ceremonial sites in the middle Iron Age, including Sites A and B at Navan Fort, Co. Armagh, Dún Ailinne, Co. Kildare, Raffin, Co. Meath and the Rath of the Synods at Tara, Co. Meath. The Rath of the Synods may be of particular importance due to its proximity to Lismullin: the second phase of activity comprises three apparently successive circular timber palisade enclosures, 25 m, 16.5 m and 30 m in diameter, which have very general similarities to the inner enclosure at Lismullin.

Despite this apparent similarity in construction, the differences between these sites and Lismullin are striking. The deliberate choice of a discreet landscape setting is in stark contrast to the location of other Iron Age ceremonial enclosures on prominent hilltops. In addition, the use of relatively small posts at Lismullin is very different from the large timbers characteristic elsewhere, most strikingly at the ‘forty metre structure’ at Navan Fort. Furthermore, the use of freestanding timber as the apparently sole construction medium at Lismullin differs from the complex of earthworks and slot-trenches to be found elsewhere. This serves to underline the unique nature of Lismullin and its significance in the Irish archaeological record.

Prehistoric Ritual

A sequence of prehistoric pits was uncovered at the south-east of the Lismullin site. The three earliest phases are undated. These were succeeded by a series of small pits, three of which may have contained wooden posts to support a superstructure or platform. A range of round-bottomed Neolithic pottery, including Early Neolithic Carinated Bowls (3850–3700 BC) and Middle Neolithic broad bowls (3500–3000 BC), was found in these features and associated with small quantities of possible human bone fragments. These were succeeded by a larger, oval pit containing sherds of Beaker pottery (final Neolithic/Early Bronze Age) in association with a broken Bronze Age polished macehead. All of these pits were sealed by a thin clay deposit, which contained what may be small fragments of cremated human bone. Although the exact function of these pits remains unclear in advance of post-excavation analysis, the occurrence of the pottery and the macehead in association with the human bone fragments indicates that they were of a ritual nature. Further final Neolithic/Early Bronze Age activity at the site consisted of a small pit at the northern corner of the site that contained 204 sherds of domestic Beaker pottery. A small ring-ditch located at the south-east of the site is as yet undated, but may prove to be broadly contemporary with either the Bronze Age pits or the later post enclosure.

The Broader Landscape

The site is located c. 500 m from Rath Lugh, a defended enclosure, which dominates the south-eastern views from Lismullin. In addition, a defended enclosure at Rathmiles is 1.9 km due west of the Lismullin enclosure entrance, while the Hill of Tara is visible 2.1 km to the south-west. The sites at Rath Lugh and Rathmiles, together with defended earthworks known as Ráith Lóegaire and Ringlestown Rath and a linear earthwork at Riverstown, have been interpreted as defensive outposts on the periphery of the Tara hinterland, dating to the final few centuries BC and the first few centuries AD. Ceremonial activity at this time was centred upon the Hill of Tara. The earlier date of the Lismullin enclosure, its contrasting construction and siting and its location on the opposite side of the Gabhra Valley would suggest a discreet separation of ceremonial activity within the Tara landscape.

In addition, the skeletal remains of a medium-sized dog were deposited in a crescent shaped pit or kiln located 65–70 m south-east of the post enclosure. Dog burials are known from both Iron Age and early medieval sites. It is possible that the burial of the Lismullin dog may have had ritual significance associated with the Iron Age ceremonial activities at the site; at the time of writing, radiocarbon dates for the dog burial are pending.




The Lismullin post enclosure is one of the most exciting archaeological discoveries of recent times. A striking feature of the site is its deliberately chosen landscape setting. That this discreet area within the Tara landscape was revisited and reused over a number of millennia can be seen in the recorded features dating to the Early and Middle Neolithic, the Early Bronze Age, the early Iron Age and the early medieval periods.

Furthermore, the vast majority of the prehistoric activity, although somewhat episodic, appears to have been of a ritual or ceremonial nature. This further emphasises that the prehistoric inhabitants of the Gabhra Valley perceived this area as a special place. By the early medieval period the focus of activity at the site had assumed a more functional nature. This can be inferred from the probable exploitation of local tillage resources and their processing in some of the various kilns on the site. The souterrain may have been used to store the dried grain and safeguard it, and the local landowners, in times of danger and attack.Thus far, the Lismullin excavations have offered us a tantalising glimpse at the archaeology and early history of the area. It is to be anticipated that the completion of the excavations and the subsequent programme of post-excavation analysis and publication will significantly enrich and broaden our knowledge of this rich archaeological landscape.




Archaeologists excavating and recording stake-holes, with box section (foreground) through two of the stake-holes. Photo: Mary Deevy Aerial topographic survey overlaid with plan of the enclosure, souterrain and ring-ditch. Also shown is a ring-ditch beyond the roadtake, which was newly identified through geophysical survey. (BKS Surveys Ltd)

Early Medieval Land Use

A souterrain was located at the brow of the north-west-facing slope at Lismullin, overlooking the River Gabhra. This drystone-built, underground structure was entered from the south-east, on the brow of the hill, and consists of two passages with a complex of inbuilt creep-ways and defensive stepped features terminating with a chamber or room at the end of each passage.

In addition, 13 clay-cut kilns were recorded across the site. While some have the classic figure-of-eight shape associated with cereal-drying kilns of early medieval date, there is enough variety in their construction to suggest that when post-excavation analysis has been completed, a more diverse date range and variety of functions may become apparent. Interestingly, a projecting ring-headed pin of possible late Iron Age date was recovered from the backfill of an elongated kiln adjacent to the north side of the post enclosure.

(Directors Excavation Progress Reports detailing the progress of the Lismullin excavation can be viewed online at:
http://www.nra.ie/Archaeology/NationalMoumentatLismullin/    )