PROMONTORY FORTS (Medieval Ireland)

A promontory fort is a fortified coastal headland or sea-girt promontory of land. The seaward sides are naturally defended by a cliff while one or more straight or curved ramparts of earth or stone, with accompanying ditches, protect the landward side. The main purpose in using a headland for fortification was to take advantage of the natural defense provided by a vertical cliff face. The location of these forts predicated engagement with the sea and maritime activity for their occupants. Many of them incorporate the Irish word dun (fort) in their name. Over 350 promontory forts have been identified on the Irish coast of which just nine have been the subject of archaeological excavation. The first scientific excavation of a promontory fort was carried out at Larribane, County Antrim in 1936 with a subsequent season of excavation in 1962. This was followed by excavations at Dunbalor on Tory Island, County Donegal in 1949, at Dalkey Island, County Dublin between 1956 and 1959 and by three excavations at the promontory forts of Carrigillihy, Dooneendermotmore, and Portadoona, County Cork in 1952. Dunbeg, County Kerry was excavated in 1981 and Doonagappul and Doonamo, County Mayo in 1999. Much of what is known about promontory forts is based on the pioneering work of Thomas Johnson Westropp who, between 1898 and 1922, visited and recorded 195 sites primarily in the west and southwest of Ireland and published twenty papers dealing with his findings. As late as the end of the twentieth century archaeologists tended to classify promontory forts as a sub-class of the less numerous inland hillforts.


Promontory forts are attributed various functions. Among the suggestions are that they may have been used as landing places for seagoing invaders and temporary refuges during inland attack. They have also been proposed as trading bases, ceremonial enclosures, observation posts, and livestock pounds. In several cases the interiors of promontory forts show no visible sign of occupation, which favors the idea that some may have served as temporary refuges.

Although there are, as yet, no firm dates for the construction of this monument type, archaeologists have tended to view promontory forts as primarily Iron Age in origin. However, evidence from excavations, Tudor maps, historical documents, and upstanding structures within promontory forts clearly indicate that occupation also took place within some of them in the early (fifth century to c. 1100) and later (c. 1100 to c. 1600) medieval periods. Three of the nine promontory forts scientifically excavated have produced substantial evidence of medieval occupation. Barry’s excavation at Dunbeg, County Kerry revealed that the first phase of occupation provided a radiocarbon date spanning the period from the end of the ninth century to the late sixth century b.c.e. However, a radiocarbon date from the innermost ditch of the promontory fort ranged from the late seventh to the early eleventh centuries c.e. proving that the fort was in use in the early medieval period. In addition, an early medieval souterrain ran outward from the entrance to the fort, and the earlier of two occupation layers within a large clochan or circular stone hut in the interior of the fort was dateable to the period from the late ninth century to the mid-thirteenth century c.e.

Childe’s excavation at Larribane, County Antrim and subsequent excavations there by Proudfoot and Wilson suggested that the fort had been built and occupied around 800 c.e. No evidence was produced however, to prove that the occupation of the headland coincided with the actual construction of the stone wall and external ditch that defended the landward side of the site. Liversages excavations on Dalkey Island, County Dublin demonstrated that a midden, datable to the fifth or sixth century c.e. on the basis of imported pottery found within it, represented the first early medieval occupation of the promontory before it was actually fortified. A second phase of occupation in the seventh century, constituting a hearth, a midden, and a possible house site, which postdated the construction of the rampart of the promontory fort, was identified in the interior of the fort. Apart from the evidence for early medieval activity found during scientific excavations, the Irish chronicles also allude to the occupation of some promontory forts during the Viking Age. For instance, Dun-severick, County Antrim was the target of a Viking raid in the ninth century, which suggests that it was a substantial settlement of some wealth in that period.

Several promontory forts enjoyed periods of occupation in later medieval times. In the late twelfth and early thirteenth centuries Anglo-Norman colonizers saw the immediate advantages of adopting and enhancing promontory forts that had previously been used as strongholds by Gaelic lords. Dun Contreathain or Don-aghintraine on the Atlantic coastline of County Sligo is, for instance, mentioned in the Irish chronicles as a base for the activities of the Anglo-Norman magnate, de Bermingham, in 1249. By 1297 the de Bermingham family had built themselves a manorial hall house within a promontory fort at Castleconnor, overlooking the estuary of the River Moy in County Mayo. At the commencement of the Anglo-Norman colonisation of Ireland, the Anglo-Norman knight, Raymond le Gros, greatly augmented the defences of an existing promontory fort called Dundonuil at Baginbun, County Wexford in order to secure an initial base for his army in May 1170 and for that which followed under the command of Strongbow in August of that year.

The results of O’Kelly’s excavation at Dooneender-motmore, County Cork perhaps best exemplifies the enduring nature of the promontory fort as a form of defended settlement. The defences of the fort were constructed in two phases. No date was confirmed for the first phase but the rock-cut ditch was modified during the later medieval period and crossed by means of a drawbridge. The parapet wall of the fort and a large two-roomed house site in the interior were also constructed in that period. In fact, no occupation levels earlier than the sixteenth century were identified during excavation.

The remarkably late use of promontory forts can also be seen on a sixteenth-century map-picture of Portrush, County Antrim made by a Tudor cartographer and at the impressive Dooncarton on Broadhaven Bay in County Mayo where a series of stone buildings in the interior of the fort constituted the homestead of a local Gaelic family as late as the seventeenth century.

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