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Dunseverick Castle

A ruined fort on top of a rocky promontory on the coast by a small inlet. The grass is green and the sky is very light blue.
Dunseverick Castle in County Antrim | © National Trust/Annapurna Mellor

Perched on the Causeway coastline on a steep-sided basalt stack, Dunseverick Castle in County Antrim is a promontory fort and an ancient royal site of the Dál Riada Gaelic kingdom. Both recorded history and archaeological studies can tell us much about the rich history of this rocky promontory.

History of Dunseverick Castle

Recorded in the Irish Annals as Dun Sobhairce, Dunseverick Castle was first fortified by an ancient chieftain, Sobhairce, from around the 5th century AD, possibly earlier and, from around the 7th century AD, was then occupied by the Dál Riada, an extended tribal group with strong maritime connections between north-east Ireland and western Scotland. It later became a centre of the Earls of Ulster around 1250–1350 AD, and then a stronghold of the O’Cahan’s and later the MacDonnells from 1560 AD.

Saint Patrick and Dunseverick

It was said that Saint Patrick once visited Dunseverick Castle where he baptized Olcán, a local man, who later became a Bishop of Ireland. The northern area of the site contains an oval depression of wet ground which is thought to be a holy well and has, unsurprisingly, become known as Saint Patrick’s Well.

Stronghold and attack

The Irish Annals tell us that the site was twice attacked by the Vikings around 871 and 924 AD as well as destroyed by a Scottish army under the command of General Robert Munro in 1642.

The final account of the castle’s capture and destruction is by Cromwellian troops in the 1650s and it appears the site was never refortified or reoccupied again.

An aerial view of a ruined fortress on a rocky promontory by the sea.
An aerial view of Dunseverick Castle | © David Craig

Archaeology at Dunseverick

While the site itself hasn’t been excavated, it’s still possible to see the surviving remains of low earthworks both on and surrounding the basalt stack.

The approach to the fort is protected by a prominent wide bank with an external ditch and with further ditches visible to the south.

The only the obvious ruin is a small residential masonry tower which stands on the south edge of the promontory. Part of it collapsed in 1978 when some of the rockface fell into the sea, but the structure was repaired and stabilised.

The summit of the fort is protected by its steep scarp slope on all sides, with a narrow break at one point which gives access to the summit. Remains of what appears to be a low embankment or wall survives around part of the edge of the summit and could be remains of a former perimeter wall or bank.

The summit appears largely flat, but it does contain low earthworks, including banks with ditches, which seem to sub-divide the summit. You can see at least three rectangular enclosures towards the southern end of the promontory, which could be the remains of former buildings.

A hand-drawn plan of Dunseverick castle based on the drawing by McNeill, 1983, UJA Vol. 46 p.107
A hand-drawn plan of Dunseverick castle based on the drawing by McNeill, 1983, UJA Vol. 46 p.107 | © Malachy Conway

Map of the site

A hand-drawn map of the Dunseverick site, based on McNeill, 1983 UJA Vol.46, p.107

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Cave excavations

To date, the only archaeological investigations at Dunseverick have been within a cave at the south end of the inlet on the western side of the promontory. During 2007 and 2008, the Centre for Maritime Archaeology (University of Ulster) and the Centre for Archaeological Fieldwork (Queens University Belfast) excavated several trenches within the cave. They uncovered remains of a rubble-built wall near the mouth of the cave which they dated to the medieval era.

Pottery at Dunseverick

Within the cave itself, excavations have revealed a sequence of archaeological deposits which contained pottery and animal bones from across the medieval period. The results so far suggest the cave was occupied in the early medieval period and that local pottery, known as souterrain ware, was probably being made at the site.

New research

The Archaeological Departments at both Queens University Belfast and University of Aberdeen are currently carrying out research at Dunseverick Castle as part of a Leverhulme funded project focusing on the early medieval kingdoms of Scotland and Ireland.

The team have been examining LiDAR imagery of the site and have carried out some geophysical surveys to help better understand the various earthwork features of the site. It’s hoped some small-scale exploratory excavations may take place.