Situated on a hillock on the SW bank of the River Boyne, with a NW-SE section of the river c. 80m to the NE. In 1172 Henry II granted Meath to Hugh de Lacy ‘as Murrough O’Maelaghlin best held it’ (Otway-Ruthven 1968, 52-3). This king of Meath died in 1153 before the province was dismembered, so in theory de Lacy’s fief, if he could secure it, was as extensive as the modern counties of Meath, Westmeath and Longford with a large part of Offaly. Hugh determined that Trim would be the caput or centre of this vast estate and commenced planning a suitable headquarters for it in a castle that would be defensively strong as well as visually impressive and capable of administering a wide area. Because one of the first accounts of the castle in the 1830s by Richard Butler (1861, 25) suggests the castle was built in 1220 this date had been followed by some later writers. However, excavation (95E0077) by Hayden (2011) in the late 1990s, together with historical research (Duffy 2011), the conservation of the structures (Cummins 2011), and a re-interpretation of an earlier excavation (E00094) by Sweetman (1978), elucidates its entire structural history beginning c. 1175.
Before any grand scheme could be started the location had to be secured, and the earliest castle was in the form of a ringwork. According to the Norman-French poem ‘chanson de geste’, known in English as ‘The Song of Dermot and the Earl’ de Lacy established a fortified enclosure at Trim in 1172 which was promptly burned by Ruaraí O’Conor and just as quickly re-built (Orpen 1898, lines 3222-9; Mullally 2002). This second phase can only have lasted until 1175 when the construction of the stone keep began at the same site. (Duffy 2011, 8)
Evidence of two construction phases of a circular enclosure (int. diam. c. 45m) was recovered in disjointed fragments outside the footprint of the keep but inside the wide fosse (Wth of top 6-10.5m; D 1.6-2.5m) that was dug around the enclosure. The fosse, whose edges were easily eroded, had not been completed at SW where there was a wide entrance gap (Wth c. 20m). At NE it was dug around rock outcrop where it probably narrowed as a consequence but this area was disturbed by later works and a quarry (dims c. 35m N-S: 11m E-W; max. D 4.5m) destroyed the outer edge of the fosse NE-SE in the middle of the fourteenth century (Hayden 2011, 217-19). The spoil from the fosse was not utilised to construct an inner bank for the ringwork. Inside the fosse at NW were the widely-spaced (c. 4-5m apart) posts (diam. c. 0.3-0.4m) of a palisade which were burnt. A large wooden structure (dims c. 10m x c. 10m) with a few widely spaced posts immediately inside the palisade at NW that had contained grain and is interpreted as a granary, also burnt down. Metalled surfaces elsewhere in the interior and a hearth outside the fosse at N also belong to this phase. (Hayden 2011, 82-91)
A second line of posts inside the first on the inner edge of the fosse at NW were unburnt and represents a re-building of the palisade (ibid. 94-6). The posts are as large and are almost as widely spaced (c. 3-4m) as the earlier palisade posts and have a connecting slot-trench. The posts are also connected to posts c. 1m behind, which would have supported a wooden wall-walk. A double-faced stone wall (L 5.2m; Wth 0.5m) at NW can be associated with this phase, but structures J, L and M from an earlier excavation (Sweetman 1978, 131-3, 143-5) can be interpreted as also belonging to it (Hayden 2011, 69-71).
The above description is derived from the published 'Archaeological Inventory of County Meath' (Dublin: Stationery Office, 1987). In certain instances the entries have been revised and updated in the light of recent research.
Compiled by: Michael Moore
Date of revision: 8 July 2019Description Source: Department of Housing, Local Government & Heritage