Ardstraw; Uí Thuirtri east of the Sperrins (collectively
known as Uí Maccu Úais); the Fir Chraíbe and the
Fir Lí west of the Bann; the Airthir around Armagh;
the Uí Chremthainn in Fermanagh, parts of Tyrone
and Monaghan; the Uí Méith in Monaghan; and the
Mugdorna, who also stretched into Meath. Branches
of the Uí Moccu Úais were in Westmeath and Meath
also. It is possible that the Déisi around Tara were
Airgialla. Originally probably subject to the Ulaid
(Ulstermen) they were gradually, from the sixth cen-
tury onwards, brought under the control of the Uí
Néill, especially by the Cenél nEógain who were
expanding from their homeland in Inishowen across
Lough Foyle and eastwards across Counties Derry and
Tyrone.
Following the defeat of the Ulaid in the battle of
Mag Roth (Moira, County Down) in 637 to 638, they
enjoyed a degree of independence from both their
former masters and the expanding Cenél nEógain.
After the devastating defeat of the Ulaid at the battle
of Fochairt in 735, the Cenél nEógain dominated the
Airgiallan territories from the shores of Lough Foyle
to the coast of Louth. The Airgialla provided military
service for the Uí Néill and propaganda was produced
explaining their evolving relationship with them.
Defeated in the battle of Leth Cam beside Armagh
in 827, they became vassals of the Cenél nEógain. It
is very likely that it was Airgiallan patronage that
helped Armagh rise to power during the seventh cen-
tury to become the chief church in Ireland. The
Airthir (“Easterners”) had control of the offices in the
church of Armagh. The Clann Sínaigh monopolized
the abbacy from 996 until the twelfth century. The Uí
Thuirtri migrated east of the Bann from 776 onwards
and lost their link with the Airgialla after 919. The
Airgiallan peoples in the midlands were absorbed by
the various branches of the Southern Uí Néill. As the
northern and southern branches of the Uí Néill drifted
apart, two kingdoms emerged as a wedge between
them. In Counties Leitrim and Cavan, the kingdom
of Uí Briúin Bréifne (later O’Rourkes) was formed.
Parallel with this kingdom to the north in Counties
Fermanagh and Monaghan and parts of Louth, a con-
solidated kingdom of Airgialla emerged, and partly
as a result of continuing pressure from the Cenél
nEógain, who absorbed their northern borders, they
moved toward the southeast. By the eleventh century
the leading family was Ua Cerbaill (O’Carroll).
Donnchad Ua Cerbaill pushed the southern bound-
aries of this kingdom to the Boyne in the twelfth
century and had the seat of the diocese of Clogher
transferred to his power center in Louth. When the
Anglo-Normans conquered Louth, this area became
known as “English Oriel” and this portion of O’Car-
roll’s kingdom was transferred to the diocese of
Armagh. The diocese of Clogher represents the medi-
eval kingdom of Airgialla.
CHARLES DOHERTYReferences and Further Reading
Bhreathnach, E., et al. “The Airgialla Charter Poem.” In Ta r a :
Kingship and landscape, edited by Edel Bhreathnach. Dub-
lin: Royal Irish Academy, 2004.
Byrne, Francis John. Irish Kings and High Kings. London:
Batsford, 1973.
Charles-Edwards, T. M. Early Christian Ireland. Cambridge:
Cambridge University Press, 2000.
O’Brien, Michael A., ed. Corpus genealogiarum Hiberniae.
Dublin: Dublin Institute for Advanced Studies, 1962.
See alsoUí Néill, Northern; Uí Néill, Southern;
UlaidAMLAÍB CUARÁN (f l. c.940–981)
Amlaíb Cuarán (Ólafr Kvaran), the son of SihtricCáech
(d. 927), belonged to the second generation of the Uí
Ímair dynasty, which came to dominate the Hiberno-
Norse world in the course of the tenth century. His
father Sitriuc and uncle Ragnall had led the return of
the Vikings to Ireland in 917 and, after eliminating
rivals to Scandinavian leadership in the Irish sea world,
they turned their attention to native dynasties. Sitriuc’s
refoundation of Dublin was secured by his victory over
Niall Glúndub, king of Tara, at Islandbridge in 919.
The following year, upon Ragnall’s death, Sitriuc suc-
ceeded as senior member of the dynasty and moved
his center of operations to Northumbria. It was there
that he died in 927. Sitriuc’s death led to the loss of
most of Northumbria to Æthelstan of Wessex, although
his brother Gofraid (927–934) and nephew Amlaíb
mac Gofraid (934–941) continued to contest control
with the West Saxons. Amlaíb Cuarán, a child when
his father died, appears in the historical record as king
of Northumbria on the death of his cousin Amlaíb mac
Gofraid in 941. Two other members of the dynasty,
“mac Ragnaill” and Blacaire mac Gofraid, the latter
based in Dublin, ruled the Irish dominions. Amlaíb
was expelled from Northumbria by Edmund of Wessex
in 943, having first been forced to undergo baptism,
and his whereabouts were unknown for two years.
In 945, the Annals of Ulster record that “Blacaire
gave up Dublin and Amlaíb succeeded him.” This
notice is immediately followed by one in which
Amlaíb and Congalach Cnogba, the new king of
Tara, were engaged in military action against the
Northern Uí Néill dynast Ruaidrí Ua Canannáin.
Because Blacaire and Congalach were implacably
hostile to one another, one can only suppose
Amlaíb’s accommodation in Ireland was arranged
for him by the king of Tara. In 946 Amlaíb plunderedAIRGIALLA