The best available description of Airghialla is given in Rev. Thomas Fee's 1950 MA thesis
("The Kingdom of Airghialla and Its Sub-Kingdoms", University College, Dublin 1950). The
following is an excerpt from the section describing Ui Breasail (pp. 72-76):

Of equal importantance among the sub-divisions of Airthir [Eastern Airghialla] were the people known
as Ui Breasail. In the sixth and eighth centuries they provided many of the abbots of
Armagh, while their prominence in secular affairs during the same period is emphasized by the fact
that at least seven of their rulers are styled kings or leaders of Airthir by the annalists. Their
name survived under the form of Clanbrassil until comparatively recent times as the designation of
that part of Co. Armagh which is in the Diocese of Dromore.

The genealogists distinguish two main branches of the Ui Breasail, descended from two sons of
Conchobar Corrach, king of Airthir, who was killed at the battle of Tellach Garraisc in 698. From
Cumascach came the line known as Ui Breasail Macha, who afterwards justified their name in a
striking fashion by their intimate association with the church of Armagh. The notable ecclesiastical
families of Ua hErudain, Ua Longain and Ua Clochagain all belonged to this branch, while of
O'Dubhagain's "Ui Breasail Iarthai" is meant to cover a section of of them - as seems probable from
an examination of the genealogies - they were the progenitors of such other well-known Armagh families
as Ua Gairbith, Ua Duibemna and Ua Conchobair. An interersting obit in [the Annals of Ulster in 953 AD]
chronicles the death of Conn mac Erudain mac Gairbith, king of Mag Duma. The editor of these annals
supposes that he was ruler of the territory which now constitutes the barony of Moycow in Co. Longford.
A comparison of this entry with the genealogies however, shows that he was really a member of the
Ui Breasail Macha, who fell at the battle of Grellach Eillte in 914. Where then was the region known as
Mag Duma, which contains the key to the location of the lands of Ui Breasail Macha? An earlier reference
to it in [the Annals of Ulster in 859 AD] describes it as "i comfous Aird Machae". The first of the three
fragmentary annals published by O'Donavan contains a detailed account of the expedition which is the
subject of the A.U. 859 reference, but for Mag Duma it substitutes the better-known Mag Macha. The
latter seems to have been situated to the west of the modern city of Armagh. Taking all things into
account, therefore, there seems little scope for error in assuming that the lands of Ui Breasail
stretched from Armagh to the River Blackwater, being bounded in the southwest by those of Ui Trena
and Ui Dorthiann and in the northeast by those of Ui Naillan. The modern village of "The" Moy on the
Blackwater is just on the confines of this territory and may be a relic of the ancient name. Still further
west Moydooey on the Monaghan-Tyrone border, and while it could scarcely be said to be "i comfhocus
Aird Machae", the name itself is strikingly suggestive. The territory of Ui Breasail Macha, being in a direct
line between Telach Oc and Armagh, was probably the first area in the neighborhood of the Primatial
church to be brought under Cenel Eogain control, and during the later medieval period much of it came
into the possession of the distinguished ecclesiastical family of O'Cuilen.

From Conchobar's other son, Buachill (ob. 754) came the Ui Breasail Airthir. This branch was not as
ecclesiastical minded as the descendants of Cumascach, but their outstanding position in political
affairs is shown by the fact that at least four of them attained, or were in line for the coveted title of king
of Airthir. They do not seem to have provided any of the Comarbada Patraic, but for over two centuries
the position of secnab in Armagh was their hereditary possession. Donngal mac Buachalla (ob. 791),
a grandson of Conchbar Corrach, was the first scion of this line to attain the kingship of Airthir. He was
followed in the same position more than half a century later by his own grandson Muiredach mac
Maelduin (ob. 863). The latter is an interesting example of the combination in a single person of the
eccesiastical and secular ruler, for in addition to holding the kingship of Airthir he was also secnab of
the church of Armagh. A grand-nephew of Muiredach's, Ceilechan mac Gairbith, appears as "dux na
nAirthir" in 933. At the same time Maelduin mac Gairbith, presumably his brother, was secnab of Armagh.
This Ceilechan mac Gairbith was progentior of the well-known family of Ua Ceilechain, who appear
regularly on the pages of the annals as kings of Ui Breasail during the eleventh century. An Ua Ceilechain
was leader of an Ui Breasail military force which sought to intercept a Cenel Eogain raiding party in
Cenach Macha in 1021. Archu Ua Ceilechain, king of Ui Breasail, was slain by the Ui Echdach in 1037.
Niall Ua Ceilechain, king of Ui Breasail, and his brother Trenfher were blinded by a rival dynastic group
in 1044. A son of Archu supra, was slain by the men of Fernmag in 1054. Henceforward the family
seems to have concentrated on ecclesiastical positions. Matudan Ua Ceilecain was secnab Ard Macha
in 1063. His son Gillapatraic held the same office at his death in 1089. Between the two appears a
secnab of a different surname - Mac Digde Ua Lorcan - whose death is recorded in 1079. But although
his surname was different, it is quite likely that the position was not allowed to go outside the sept, for
O'Dubhagain names Ua Lorcan as lord of Ui Breasail Airthir. With these last hereditary office-holders
the post of secnab at Armagh comes to an end, and shortly afterwards the last representatives of the
Ui Breasail line disappear from the annals.

The bishops of Armagh from the Ui Breasail line:

Ailill (d. 526), Ailill II (d. 536), Cele Petair (d. 758), Airechtach (d. 794)

Kings or leaders of the kingdom of Airthir from the Ui Breasail line:

Ronan (son of Tuathal - d. 625), Conchobar (son of Maelduin - d. 698), Cumascach (son of Conchobair - d. 743),
Donngal (son of Buachalla - d. 791), Muiredach (son of Maelduin - d. 863), Ceilecan (son of Gairfidh - d. 933),
Ua Ceilecan (d. 1077)

Rev. Thomas Fee's 1969 paper " The Church of Armagh under Lay Control" discusses how some branches of the Ui Breasail briefly took over key church positions about 1000-1100 AD. One of these families was O'hErodain (Heron).


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