Shannon—the Dál gCáis. From them came Brian
Bórumha mac Cennétig (Brian Boru) who was argu-
ably the first effective high king of Ireland from
Munster. Brian dominated Munster and soon made
his claim for the kingship of Ireland. His defeat at
the battle of Clontarf beside the Norse town of Dublin
highlights the reorientation of Irish politics at this
time. By supplanting the Eóganachta as the traditional
kings of Munster and the Uí Néill as the traditional
occupants of the high–kingship, Brian introduced a
new era in Irish politics. His descendants were to
play a leading role in national affairs of the eleventh
and twelfth centuries, controlling not only Dublin
but also the Isle of Man for a period. They had inter-
national agreements and marriage alliances, corre-
sponded with the Pope and Norman bishops—leading
to the twelfth century church reform—and intro-
duced Romanesque architecture. For them the concept
of Leth Moga was no longer of major significance.
CHARLES DOHERTY
References and Further Reading
Francis John Byrne, Irish Kings and High-Kings, London, 1973;
T.M. Charles-Edwards, Early Christian Ireland, Cambridge,
2000.
See alsoGenealogy; Invasion Myth
LIA FAIL
SeeInauguration Sites
LIGHTHOUSES
SeeShips and Shipping
LIMERICK
The Shannon River (Σηνοσ- Senos) features on
Ptolemy’s map of Ireland (c. 150 A.D.), which also
locates a tribe near Limerick, the Gangani, not subse-
quently known. The later settlement developed on
King’s Island—then known as Inis Sibtond—the
Érainn dynasty having a branch known as Érainn of
Inis Sibtond, who may have controlled it about the begin-
ning of the historical period. The battle at Luimnech
(c. 575 A.D.) may refer to a location in Connacht, the
earliest references to the northMunster Luimnech
occuring in a law tract (c. 700 A.D.), where the estuary
itself is intended; also, an early saint’s life speaks of
an island “in that sea called Luimnech,” and a ninth-
century tale mentions Loch Luimnig (loch here mean-
ing “estuary”).
By the sixth or seventh century, the subject peoples
of Munster were known as Déisi(vassals). The land
ofIn Déis Tuaiscirt(the northern vassalry) straddled
the Shannon near Limerick. A branch, the Uí Caisin,
included Luimnech among its lands. A parallel off-
shoot, Uí Tairdelbaig, established the kingdom of Dál
Cais across the Shannon (from which Brian Boru
descended). The introduction of Christianity to the
Limerick area is associated with Uí Tairdelbaig, the city’s
patron saint, Mainchín son of Setna (St. Munchin), being
a member of the dynasty, said to have been granted
land on Inis Sibtond by Ferdomnach of Dál Cais to found
a church (possibly the site of the modern St. Munchin’s
church).
Viking raiding parties used the Shannon from the
830s, attacking churches along its route and, by mid-
century, had established a settlement at Limerick,
building a fortress on Inis Sibtond. It was a very stra-
tegic site, protected from the west by the Shannon and
elsewhere by the Abbey River. The Viking rulers of
Inis Sibtond had access to the very interior of Ireland,
making Limerick, after Dublin, perhaps the most
important commercial center in the country. Tomrar
son of Elge, “Jarl of the Foreigners,” based himself
there in 922 to ravage the Shannon valley. By this
time the Norse kingship of Limerick, drawn from a
Hebridean dynasty, had emerged as a regional
power, challenging Dublin for supremacy of the
Irish Scandinavians.
As Dál Cais strengthened its position in north
Munster around the mid-tenth century, the potential of
Limerick was recognized. In 967, Brian Boru’s brother
Mathgamain slaughtered the Limerick Norse in battle,
burning their ships, plundering Inis Sibtond and its
fortress (dún), and the Norse king Ívar was temporarily
expelled. In 972, the Norsemen were driven out of Inis
Sibtond and the dúnwas set on fire. The subjugation
of the Limerick Norse was completed by Brian Boru
in 977, when he slew Ívar and his sons on Scattery
Island, after which the Dál Cais controlled Limerick
and maintained a fleet on the estuary. Brian may have
selected Inis Sibtond as one of his bases, if it is the
Inis Gaill Duibh (Island of the Black Foreigner) where
he built a stronghold (daingen) in 1012.
In 1016, the Dál Cais royal poet Mac Liag died at
Inis Gaill Duibh and the city featured in the struggle
in the 1050s between Donnchad son of Brian Boru and
his nephew Tairdelbach Ua Briain (d. 1086). Later,
Tairdelbach and his son Muirchertach (d. 1119) made
the city their capital and summoned provincial kings
there to make submission. Muirchertach refortified the
island defences in 1101 by demolishing the Grianán
of Ailech, royal site of the northern Uí Néill, and
commanding his army “to carry with them, from
Ailech to Limerick, a stone for every sack of provisionsLETH CUINN AND LETH MOGA