Indicated — Castle Island

Known as Mac Dermot's Rock or Castle Island (Weld 1832, 238-9), it was a centre of the Mac Dermot clan and seems to have been the symbol of sovereignty amongst them as possession of the Rock was hotly contested throughout the Middle Ages. The character of the remains have been much debated (Lynn 1985-6, 104; Graham 1988, 33; Doran 2005, 382-3). The fortification may have been constructed of wood originally and it cannot be stated definitively when or by whom the present remains were constructed, although the tower house (RO006-046001-) may be the 'great regal house' begun by Brian Mac Dermot (KM 1585-92) in 1578 (ALC, vol. 2, 423). The high status of the monument is illustrated by the fact that all its materials must have been brought out from the lakeshore. The remains are situated on a small subcircular island (dims c. 60m E-W; c. 50m N-S) at the entrance to a bay (diam. c. 600m) at the SE angle of Lough Key. The island is situated c. 250-450m from shorelines NE-SW, and there is a submerged pier or slipway (RO006-046002-) at SE. This is opposite a slipway (RO006-209----) on the mainland, c. 280m to the SE that may have served as an embarkation point for the Rock (O'Conor et al. 2010, 23). The island is largely rock, but the SE quadrant may be an artificial construction (ibid. 22). The earliest reference to the Rock is in 1159 when Diarmuid, son of Tadhg Ua Maelruanaidh (KM 1124-59) died there (Ann. Tig. 1159, 2). In 1187 (AFM) or 1184 (ALC) the Rock was struck by lightning and Duvesa, the wife of Conor Mac Dermot (KM 1186-97), together with over a hundred people burned or drowned (AFM 3, 77). It was briefly held by the Justiciar Maurice FitzGerald in 1235 after a siege (R)006-046003-), but levelled by Conor Mac Dermot when he recaptured it (AFM 3, 281, 283). FitzGerald was avenged in 1249 when he returned to plunder Lough Key and the Rock (AFM 3, 337). In 1321 the Rock was burned by Cathal, the son of Donnell O'Conor, and in 1342 it sheltered the unpopular Turlough O'Conor. In 1401-02 it was disputed between different branches of the Mac Dermots (AFM 4, 773, 775), and again in 1478 when wooden engines were employed against it (AFM 4, 1109). Possession was disputed again in 1488 (AFM 4, 1163) and in 1534 (AFM 5, 1417). It's greatest moment must have been in 1540 when Rory Mac Dermot (KM 1549-68) and his wife, Sadhbh Burke McWilliam, entertained lavishly at Christmas (ALC 2, 327; AFM 5, 1459) on the Rock. It may have been abandoned shortly thereafter, although it was confirmed to Bryen Mc Dermode in 1585 (Freeman 1936, 162), and it featured in military campaigns down to the end of the seventeenth century. In 1652 it was surrendered by Terence Mac Dermot to the Cromwellian Reynolds, and thereafter the Rock and its lands were granted to the King family. In the early 19th century it was consolidated and the buildings extended by the King family who used it as a fishing lodge. The original structure may have been the oval enclosure (int. dims 37m NE-SW; 26.4m NW-SE) defined by a masonry wall (T c. 1.5m; H c. 3m) which is largely 19th century re-building, but which may have functioned as an island cashel occupying most of the rock island. The crenelations are 19th century, but the lower mortared wall with larger stones may have been re-vamped from an original cashel when the tower house (RO006-046001-) was added in the 15th or 16th century. The monument was illustrated by Grose (1791, vol. 1, 85, Pl. 79) before it was developed as a fishing lodge in the early nineteenth century, probably to a design by John Nash. Grose’s drawing shows both a tower and the wall of the enclosure, so these features are not entirely the result of Nash’s work. Archaeological excavation (19E0348) inside the enclosure at W demonstrates that the earliest occupation was in a cashel, the wall of which (Wth 3m; max. H c. 1m) with an entrance (Wth c. 1m) was found inside the wall of the present enclosure. No artefacts are associated with the cashel, but the wall was sealed by an extensive layer of burning (T 0.02-012m), which the excavator equates with the disastrous fire of 1184. After this burning clay was introduced to level up the area for a high medieval building with drystone walls (T c. 1m) and a clay floor. A second drystone structure was built against the S wall of this building after its demise. (Finan 2019; excavations.ie 2019: 403) The tower house can be identified as a masonry block (int. dims 9.15m NW-SE; 5.7m NE-SW) with strong walls at the core of early 19th century additions to the NE and SW. There is a garderobe chute (dims. 1.2m x 0.3m) in the NE wall (T 2m) and a blocked window (Wth 0.4m; H 1.7m) with an external chamfer is in the SW wall at the first floor. Underwater survey reveals that there is extensive midden material dating from the nineteenth century offshore to the SE. (O'Conor et al. 2010) This is a National Monument in state guardianship: No. 586 See the attached view taken from the SE Compiled by: Michael Moore Date of upload: 24 August 2010 Amended: 30 October 2020