1991:045 - DUNDRUM CASTLE, Dublin, Dublin

The fifth and final season of excavation took place during the month of July 1991 (funded and serviced by Rathmichael Historical Society).

Examination of the 13th-century castle, of which only the lower part of the north-west facing wall (built against the side of the moat) has survived, indicates that the drawbridge entrance was located at the western corner of the structure. Nothing has survived of the remaining three walls. Neither was there any indication that the very substantial moat, located along the length of the north-west facing wall, turned at either end of the wall to encompass the castle. Examination of a cavity beneath the central drawbridge slot revealed that the face of the main wall beneath the drawbridge was flat beneath the two easternmost slots, but the batter re-commenced beneath the third slot and could be traced for a further 0.6m towards the western corner. The western corner of the 13th-century castle was located beneath the fireplace wall of the 16th-century castle, at a point 0.5m south-west of the drawbridge structure. Evidence that the moat did not continue for any distance beyond the line of the drawbridge wall was indicated when a stone-lined well was discovered approximately 6m south-west of the above-mentioned western corner of the castle. A trial trench, dug in Area 3, between (and level with) the well and the 13th-century castle produced damp clay, with silt appearing at a depth of 0.8m. Coring from this point, revealed grey wet silt at a depth of 0.9m and water at 0.96m (i.e. 2.35m from modern ground level).

Neither moat fill nor artifacts were recovered from the trial cutting or cores. The well which was excavated to a depth of 3.2m had been backfilled with boulders and rubble including pieces of red-brick. At several points in the well lining, parallel wooden poles had been inserted, and voids in the stonework indicated where others had been located. They were positioned at approximately 0.5m intervals, and may have acted as ladders, although it is difficult to see how they could thus have been used, as the well filled with water to within 0.6m of the top within a few days of excavation. The lack of finds indicates that the well was probably of the covered variety and associated with the 16th-century castle. However, the finding of large sherds from a 13th/14th-century vessel in the mud near the well may be an indication that there could have been an earlier well or spring at the same spot.

The vertical shaft (Excavations 1990, 25–26) located at the eastern end of the 13th-century wall, was further examined. This is a latrine shaft, with a cleaning sluice in the form of arched openings, at the base. The opening examined last season emptied into the moat, but the opposite opening, examined this season, was built against boulder clay. However, a small spring located at its outer edge ensured that the base of the shaft was continuously filled with water. The silt at the base of this ope also contained waterlogged pieces of wood, i.e. the remains of plank centering used when constructing the arched tunnel. This second ope was located at the base of the east-facing corner of the castle wall.

A cutting was opened vertically down the face of the wall in order to locate the sluice opening. This revealed that the outer stonework was extremely rough and uneven, i.e. it had been built directly against the boulder clay and was never intended to be seen. It was not therefore possible that the moat continued around this side of the castle, probably because the ground slopes sharply to the river at this point.

Material recovered from the moat suggests that it was allowed to fill with domestic refuse and layers of redeposited clay over a comparatively short period, thus effectively burying that part of the structure which was built against the side of the moat. When the 13th-century castle was demolished in the late 16th century in order to supply building material for the 'new' castle, this buried structure was the only part of the original castle which survived, apart from one area around the drawbridge incorporated into the 16th-century structure.

A structural feature relating to the building of the 16th-century castle was uncovered during the investigation of the area around the well. This was the discovery that at this point a relieving arch, resting directly on the sub-soil, forms part of the foundation course for the tower wall.

121 Barton Rd East, Dundrum, Dublin 14