Ireland By Boundaries

Ulaidh (Ulster)

Ulster’s early story extends further back than written records and survives mainly in legends such as the Ulster Cycle.

The Ulaidh were a powerful northeastern branch of the Érainn / Fir Bolg people. Their name has been reconstructed as “Uluti” (deriving from ul, “beard”). The tribe’s ruling dynasty claimed descent from the legendary king Rudraige.

Their principal stronghold was Eamhain Mhacha / Navan Fort, near Armagh. This appears on Ptolomey‘s C2nd map of Ireland, where they are identified as the Volunti / Voluntii and adjacent Darini. In their prime they seem to have been direct rulers of what are now County Monaghan, County Armagh, County Down, County Antrim and northern County Louth.

At their height, Ulaid territory extended south as far as the River Boyne and as far west as modern County Leitrim. The centre of the province was held by the Airgíalla, who were vassals of the Ulaid, and later the Uí Néill. Ptolemy’s map lists two tribes further west, the Vennikinii in County Donegal and the Erpitianni along lower and upper Lough Erne; both were probably subject to Ulaid rule.

According to the Annals of the Four Masters, the reduction of the Ulaid began in 331 AD, when the Three Collas defeated their king Fergus Foga in the Battle of Achadh Leithdheirg in modern County Monaghan. They seized all their territory west of the Newry River and Lough Neagh, and burned Emain Macha.

By early Christian times the northern Uí Néill (a branch of the Connachta) has pushed the Ulaid into to eastern County Down where they became known as the Dál Fiatach and the Dál nAraidi.

The Dál Fiatach held on as kings of Ulster against further attacks by the Uí Néill, and were still ruling part of County Down, based at Downpatrick, until they were overwhelmed by the Normans in 1177. Their lands were taken by John de Courcy (d.1219), then by Hugh de Lacy (d.1243), who founded the Earldom of Ulster, extending from the Mountains of Mourne to the Glens of Antrim.

The Uí Néill / O’Neill dynasty dominated most of medieval Ulster from their base in Tír Eóghain (“Eoghan’s Country”), most of which is now in County Tyrone.

The Earldom of Ulster passed into the hands of the Norman de Burgo clan, who ruled Connacht, but collapsed in 1333 when it was superseded by the Clandeboye O’Neills.

The first O’Neill king of Ulster was proclaimed in 1364.

Ulster’s second most powerful clan was the Ó Domhnaill / O’Donnell dynasty who ruled over Tír Chonaill (“Conal’s Country”, now County Donegal) from the early C13th until the beginning of the C17th.

By the end of the C15th Ulster was the only Irish province completely outside English control and was the last redoubt of the traditional Gaelic way of life.


The  Grianán of Aileach / Grianán Ailigh, a hillfort on top of Greenan Mountain in modern County Donegal. The restored fort stands in a commanding position at the base of the Inishowen peninsula overlooking Lough Swilly to the west and Lough Foyle to the east. (Photo by Jon Sullivan)

The “kingdom” of Aileach / Ailech, part of the northern Uí Néill /  Cenél nEógain territory from the mid-C5th, was ruled from c.700 by a branch that shared its name with the royal hillfort. The fortress itself was destroyed in 1101 by the king of Munster, Muirchertach Ua Briain.

In the late C12th the kingdom lost a lot of territory to the invading Normans, who controlled extensive lands once held by Aileach by around 1177.

The last two chieftains were Aed In Macaem Toinlesc Ua Neill (1167-1177) and Mael Sechlainn mac Muirchertaig Mac Lochlainn (1177-1185), after whose death the Cenél nEógain ruled as kings of Tír Eógain. The last to actually be styled king of Ailech was Áed Buide Ua Néill (died 1283).

Airgíalla / Oriel

AirgíallaAirgeala / Oriel, aka OiriallaOrgiall, Orgialla, Oryallia, Ergallia, Uriel, was a historical region that at its height roughly spanned large parts of the modern Counties of  Louth, Armagh and Monaghan. It was controlled from around the late C6th to the late C16th by a loose confederation of nine mainly unrelated dynasties called the Airgíalla, descendants of  the Three Collas that had defeated and killed Fergus Foga, the last Ulaid king, at the Battle of Achadh Leithdheirg  in 331 AD and subsequently burned Eamhain Macha / Navan Fort.

(The term Airgíalla was long believed to have derived from orgialla – “hostage of gold”, in accordance with a legend that the Collas had stipulated that if any chiefs of the clan Colla were at any time demanded as hostages, their shackles should be of gold. It has also been proposed as a cognate of the Scottish Argyll / Argyle, possibly referring to Gael or East Gael. However, recent research suggests that it is derived from Airgíallne – “additional clientship”.)

There were times when there was no one supreme king of  Airgialla / Oriel, with two or more kings ruling portions of the territory. The over-kingdom of Airgíalla was itself composed of nine sub-kingdoms, named after their ruling dynasties. They were called the Uí Moccu Uais (the most powerful), Uí Chremthainn (a lesser offshoot), Uí Thuirtri, Uí Meic Cairthinn, Uí Fhiachrach Arda Sratha, Uí Méith, Uí Cruinn, Ind Airthir and Mugdorna. 

Territory shown on late maps includes Dartraighe / Dartrey, identified with an early tribe and thought to mean “calf people”. Their lands stretched west along the River Erne through the region which became known as Breifne.

In early manuscripts the Bishop of Clogher was styled Bishop of Oirialla.

The last king of Airgíalla / Oriel was Sir Rossa Buidhe mac Airt (1579–1589).

Tír Chonaill

Tír Eoghain





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