2017:410 - Oisín House, 212/213, Pearse Street and the Printing House, Trinity College, Dublin 2, Dublin

This report pertains to a large-scale development at Oisín House and in the environs of the Printing House, a Recorded Monument and Protected Structure (No. 2003) in Trinity College. This iconic building was designed and constructed in 1734 by the architect Richard Cassels and an east-west extension was added in the mid 19th century with a second extension, set at a slight angle, in position by 1910. Oisín House is located on Pearse Street, formerly Great Brunswick Street which borders Trinity College on the north. This area was originally low-lying ground, the original street being further north towards the Liffey.
Land reclamation began in the late 1600s; along the river frontage timber revetments dated to this period were found along Townsend Street, all associated with the forming of the new parish of St Mark in 1798, centred on the church. To the rear of this the area was developed by the construction of 18th-century houses, streets and alleyways, as represented on Rocque’s map of Dublin. Great Brunswick Street was laid out as part of the Wide Street Commissioners work after 1756. Rocque’s map records the Printing House, accessed by Carter’s Lane along the northern side (along the Pearse Street Lane) with a mix of domestic, non-domestic and yards and gardens occupying the site of Oisín House and its environs.
The main programme of works was the demolition of Oisín House, a modern construction built in 1972, demolition of the 19th-century extensions to the Printing House, and the demolition of a number of small single-story store rooms along Pearse Gate lane, on the eastern side. This entire area was then excavated down to the bedrock and beyond.
The first phase of monitoring involved the excavation of engineering test-pits in and around the Printing House. Along Pearse Street Lane, infill deposits were found comprising brick, mortar and clays up to 1.2m in depth and this was found to extend around the front of the Printing House with no evidence of any structure located. This general infill was a major project in Trinity from the mid 18th century onwards, which saw the entire college complex raised up by between 1m and 2.5m. The infill was provided by the demolition of the first quadrangle dated to c. 1592 and other ancillary buildings along with organic refuse from the college and clays, possibly from excavation of basements. On the southern side of the eastern extension to the Printing House the testing revealed infill deposits to 1.6m in depth, sitting over what appeared to be grey silt with some cockle shell a depth of 3m. A timber tenon was found in the upper levels which suggested there may originally have been a timber reclamation revetment somewhere in the vicinity although none was found during the subsequent monitoring programme.
The monitoring programme established that the construction of Oisín House, with its basement car-park, had completely removed any surviving archaeological remains within this footprint. Thus, the monitoring did not produce any results within a major portion of the site. However, beyond the Osisín House footprint, on the western side and running along what was probably part of Carter’s Lane (now Pearse Street Lane), deposits and structures were found after the removal of the sheds and the limestone boundary wall along the eastern side of the lane.
These works, initially in a trench 3.5m in width (east-west), exposed a truncated early (18th-century?) brick drain in the south-west corner of the trench (in the south section), which was likely to be the earliest feature on site and was at a similar level to the base of the Printing House. At a distance of 1.8m to the north of the Printing House, the remains of a substantial stone wall were exposed running along the western side of the cutting, measuring approximately 11.8m in length and orientated north-south. The wall has returns eastwards on either end, which may suggest it was originally a building but these were removed during the construction of Oisín House. The wall/building is very solid but cannot be identified on Rocque, as there are gardens in this location in 1756. Thus, it is likely to date to slightly later. The wall foundations extended to 1.2m in depth and were 0.6m in width, bonded with a white cementatious mortar. In addition to this building, traces of a second limestone wall were also exposed 1.1m to the east, which was badly damaged by the Oisín House basement wall (which was on the same alignment).
Beneath the stone building, the biggest feature was a large brick culvert (Culvert no. 1), orientated north-east/south-west, and lying roughly 2.1m below present ground level. The arched culvert was intact along the southern half of the trench and found to measure internally 1.2m in width by at least 1.3m in height, with evidence of a slab floor. The eastern side wall was fully exposed where the head was removed and this measured 0.6m in width by 1m in depth. The structure was well-built, composed of small limestone stones, averaging 0.1m by 0.15m, all mortared with off-white mortar. A second culvert, similarly built but smaller, fed into the culvert from the south-east side and this was re-used as a foul drain and was somewhat disturbed. Several drains were also identified, feeding into the culvert.
The excavation beneath Oisín house produced a stratigraphy of between 1.5 to 2m of riverine silts and gravels, neither containing no artefacts, sitting over limestone. There was no evidence of any revetments or earlier structures.

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