2005:009 - RATHLIN ISLAND: Bruce's Castle, Ballycarry, Antrim

An excavation was undertaken at Bruce’s Castle on Rathlin Island, Co. Antrim, from 20 June to 1 July 2005. The work was conducted by the Centre for Archaeological Fieldwork, School of Geography, Archaeology and Palaeoecology, Queen’s University Belfast, on behalf of the Environment and Heritage Service: Built Heritage, as a component of the fieldwork programme being undertaken on the island by the Centre for Maritime Archaeology at the University of Ulster at Coleraine.

The castle was discussed in McNeill’s overview of the stone castles of north Antrim (1983, 104–6), but, other than some references to its existence in 16th-century texts, its origins and earlier history are poorly understood; it is reputed to be the ‘rycht stalwart castell’ referred to in John Barbour’s 14th-century poem ‘The Bruce’, where Robert the Bruce sought sanctuary on the island during the winter of 1306–7. The monument is located on the island’s eastern coastline and comprises a basalt promontory surrounded on three sides by cliffs, with an outer bank, ditch and inner bank restricting access from the landward side to the north-west. These earthworks enclose a subrectangular area—the outer ward—that measures c. 57m from north-west to south-east by 47m.

From the top of the outer bank, the ditch slopes southwards down to a flat-bottomed base. The width of the ditch varies between 2m and 2.5m for most of its length. From the base of the ditch, the inner bank slopes steeply upwards towards the south, forming a bank that is for much of its length almost 1m higher than the outer bank. The surviving evidence suggests that the inner bank was crowned with a mortared curtain wall, while at the west corner of the outer ward three sections of mortared stonework were identified jutting through the turf layer. In addition, two massive fragments of mortared masonry lie in the ditch opposite this corner, in a position that suggests that—prior to their collapse—they formed part of a perimeter tower that once stood at the south-west end of the inner bank. A subrectangular earthen platform extends for c. 10m from the north-east corner of the inner bank, disturbing the line of the ditch. This projection was described by McNeill (1983, 104) as the site of a ‘nearly circular angle-tower’, but no mortared masonry was noted on the platform during the recent programme of fieldwork.

The inner ward occupies a small rectangular sea-girt rock outcrop to the south-east end of the promontory; this outcrop measures c. 20m from north to south by 40m, and is connected to the main promontory by a narrow basalt land bridge. The remains of a mortared stone wall, 18m in length by 1m in thickness, follows the line of the northern cliff-edge, while at the south-west corner there is a small mortared stone embrasure; these features probably represent the remains of a mortared stone wall that enclosed the circumference of the inner ward.

A scheduled monument, the investigation focused on a study of the outer ward’s defences, with a 1m (south-west to north-east) by 9m trench excavated by hand across the inner bank and ditch in an area where cattle poaching had caused damage. The reinstatement of this damaged area following the excavation was part of the programme of work. The outer bank lay beyond the north-western limits of the excavation trench and was not investigated. The first phase of activity at the site involved the cutting of the ditch into the basalt bedrock; the ditch proved to be some 5m wide at its base and flat-bottomed. At the south-eastern side of the trench a sloping stone-lined facing to the inner bank was encountered, with the stones set in mortar, rising up to provide the foundation footings for a badly decayed mortared stone wall, some 0.5m thick, crowning the top of the inner bank. There was no evidence to suggest that the ditch had its origin at a date earlier than the medieval period, and it can be suggested that the stone wall represents the remains of a medieval curtain wall that defended the outer ward’s landward side and which was connected to the now collapsed perimeter tower at the south-west end of the inner bank.

A second phase of activity was marked by the presence of three distinct basal deposits on the floor of the ditch, including a 0.2m-deep mortar-rich grey silty clay containing rotted mortar present towards the south-east side of the ditch, and a deposit of similar grey silty clay, 0.3m in thickness, at the north-west side of the ditch, containing particles of a mineralised iron-rich orange flecking. A further deposit of grey silty clay, 0.1m thick, was also present across the rest of the base of the ditch. It could be argued that these deposits accumulated in the ditch base during the medieval period, although the deposits associated with the next phase of activity (Phase 3) would suggest that the site had then become abandoned, since the grey silty clay fills in the ditch were overlain by a deposit of grey/brown silty clay which contained frequent flecks of washed-out mortar, and a large quantity of angular basalt pieces. This deposit was some 0.5m deep and was also shown to lie against the mortared stone facing to the inner bank at the south-east end of the trench. A 0.5m-thick deposit of dark-brown clay that also contained large angular basalt stones was found to the inner, south-eastern side of the curtain wall. Both of these deposits were judged to represent the collapse of the curtain wall.

There then appears to have been a second period of fortification (Phase 4), when the medieval defences were remodelled by the introduction of a series of deposits of varied composition and collectively up to 1m in thickness. These deposits included layers rich in laterite and other minerals, layers of brown clay, grey/brown clay and red/brown clay, and deposits of sod-like material. The upper surface of the series of deposits was compacted (e.g. C206, a 0.1m-thick laterite-rich layer deposited to the rear of the old curtain wall) and, taken in conjunction, the introduced layers made up a sloping rampart that was built over and against the old medieval defences and the Phase 3 abandonment layers.

The historical evidence would suggest that the castle was in use during the late 16th century and that it was besieged and captured from the MacDonnells in 1575 by an English force led by Captain John Norris, who, having massacred the defenders and islanders, then withdrew leaving a garrison in the castle to hold the island (Brewer and Bullen 1868, 17). This involved expenditure on repairs to the castle’s fabric, although it was subsequently abandoned by the English by the end of the year. It can be suggested that Phase 4 either represents the MacDonnells’ efforts to refortify the castle, perhaps in 1568 when Sorley Boy MacDonnell was reported as having fortified the island (CSPI 1860, 363–4) or in advance of the English attack in 1575, or that it represents the work undertaken by the English garrison to repair the castle’s defences during their time there. The subrectangular earthen platform that extends for c. 10m from the north-east corner of the inner bank and which disturbs the line of the ditch should also be considered at this point. It could be that this platform represents the remains of an earthen bastion added by the English to provide additional flanking strength to the revamped medieval defences.

After this period the site again appears to have fallen into disuse, with a series of post-abandonment layers laid down during Phase 5. The base of the Phase 4 rampart was overlain by a mid-brown silty clay containing angular basalt stones, while the main body of the rampart was covered by a layer of sterile mid-brown silty clay that was present across the entire area investigated. Early modern activity (Phase 6) was represented by a now decayed drystone field wall that was constructed over the line of the old curtain wall, while the entire trench was covered by a turf layer.

References
Brewer, J.S. and Bullen, W. (eds) 1868 Calendar of the Carew Manuscripts, Volume 2, 1575–1588. London.
CSPI 1860 Calendar of State Papers relating to Ireland, Volume 1, 1509–1573. London.
McNeill, T.E. 1983 The stone castles of northern County Antrim. Ulster Journal of Archaeology 46, 101–28.

School of Geography, Archaeology and Palaeoecology, Queen’s University Belfast and University College Dublin