Grianán of Aileach | An Grianán Fort

Grianán Ailigh

Grianán of Aileach

Grianán Ailigh

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From its lofty vantage on top of Greenan Mountain, the spectacular Grianán of Aileach (also known as An Grianán Fort) is one of Ulster’s most iconic monuments.

The Grianán of Aileach, also known as An Grianán Fort, takes its name from ‘Grianán Ailigh’ that broadly translates to the ‘stony palace of the sun’, and if you’re lucky to be there around sunrise or sunset on a clear day you’ll see it is well named. The Grianán of Aileach is truly beautifully positioned on Greenan Mountain overlooking the valleys of the Foyle and Swilly rivers. Giving it extensive views over one of the most stunning parts of Ireland. It is an impressive circular fort, that has a diameter of 23m (76 feet), with drystone walls that stand around 5m (16 feet) high. The top of the walls can be reached by a series of steps and terraces.

Beyond the fort the ramparts may provide evidence that this spectacular location has been an important place for millennia. As the stone fort is surrounded by a series of three enclosing banks and ditches, though these are difficult to discern today. These may represent the remains of a hillfort dating to the late Bronze Age or early Iron Age A well dedicated to St. Patrick can be found on the southern side of the hill, and further indication of ancient activity here can be found with the ‘tumulus’ recorded on the hill to the southeast of the drystone fort, this feature may represent the remains of a cairn or possibly a Neolithic passage tomb given its elevated siting in the landscape.

The History of the Grianán of Aileach / An Grianán Fort

The fort was once the ancient royal seat of the Cenél nEógain, who were a branch of the Northern Uí Néill, one of the most powerful and influential of Ireland’s early medieval dynasties. It appears in the Dindshenchas a set of early medieval poems about the origins and traditions of places. Some of that work can be attributed to Flann Mainistrech of Monasterboice who died in 1056. The Dindshenchas refers to the Grianán of Aileach as a ‘lofty castle’ and ‘honoured above hills like the silent Hill of Tara‘. 

Aileach Frigrenn, faithche na ríg rígda in domain
dún cos’ roichdis róit fo gregaib tre chóic clodaib.

Aileach Frigrenn, green-sward of the world’s royal kings,
fortress to which led roads horse-trodden, through five ramparts.
(Dindshenchas).

One of the famous kings of the Cenél nEógain was the High King Niall Glúndub. He was a powerful figure in 10th century Ireland, a noted warrior, who became embroiled in wars against the Viking Ívarr Dynasty, who had arrived in Waterford and Southern Leinster in 917. After a number of campaigns, Niall Glúndub and the Uí Néill were comprehensively defeated near Dublin in 919. This was a disastrous defeat not only for the Uí Néill, but also for their allies as a number of Irish kings were killed. A tradition relates how Niall Glúndub was buried in the cairn on the summit of Tribadden Mountain, though this is likely to be the result of a conflation of the site of the battle at the ‘Fords of Cill Mosamhog’ with the modern name Kilmashogue.

It is thought that the Grianán of Aileach was the main royal residence of the Cenél nEógain until around the late 930s, when they moved to Tullaghoge in Tyrone. The Annals of the Four Masters record how the true end of the fort came to a shocking conclusion in the year 1101, when the King of Munster Muirchertach Ua Briain, demolished the fort. This was in retaliation for an outrageous event in 1088, when the Cenél nEógain and Uí Néill defeated the men of Munster and marched to the Ua Briain royal site at Kincora, and forced them to cut their hazel trees and to carry the timber all the way back to Ulster to use the wood to roof a hall in the Grianán of Aileach. In revenge, when Muirchertach Ua Briain conquered the armies of the Uí Néill, he made the defeated warriors carry stones from the fort back to Munster.

Ní chuala coinnmheadh neimhir,
Ciat chuala coinnmheadh muirir
Gar coinnmheadh cloche Oiligh,
For ghroighibh flatha Fuinidh

I never heard of the billeting of grit stones,
Though I heard of the billeting of companies
Until the stones of Oileach were billeted
On the horses of the King of the West
(Annals of the Four Masters)

For more on the history of this iconic site and the Cenél nEógain I recommend The Kings of Aileach and the Vikings, AD 800–1060 by Darren McGettigan.

The Grianán of Aileach was visited by John O’Donovan and George Petrie during the Ordnance Survey in the 1830s, though by the later 19th century the fort was deemed to be in a precarious condition. Extensive repair and restoration was carried out by Walter Bernard between 1874–1878 and the appearance of the stone fort today is largely due to that work.

Visiting Grianán of Aileach – Information

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