Assessment
Historians debate the importance of Diarmait Mac
Murchada. Arguing counterfactually, they question
whether, even had he never appealed to Henry II, the
situation would have been very different. Sooner or later,
it has been said, an English king would have turned to
a conquest of Ireland. Diarmait was merely a facilitator.
Perhaps, but conquest did not necessarily have to take
the form it did in Ireland. The “Normanizing” kings of
Scotland, notably David I (1124–1153), show that
Anglo-Norman culture could become influential by sub-
tle infiltration as well as by invasion. It is therefore still
open to question whether Diarmait’s submission to
Henry II made a full conquest of Ireland inevitable.
Another theme that has been stressed is that Diar-
mait’s actions were not so extraordinary. In twelfth-
century Ireland, kings were willing to adopt new
methods to achieve and sustain their power. We
should remember that requests for foreign aid were
not exceptional and were naturally directed to the
military source closest to hand. Ulster, for instance,
had intimate contacts with the western isles of Scotland.
As recently as 1154, Muirchertach Mac Lochlainn had
hired a fleet from the isles led by one Mac Scelling to
counter the naval power of Tairrdelbach Ua Conchobair.
Mac Murchada’s contacts in Leinster lay east and
south; so it was that in 1166 he set sail for Bristol.
These views have won general acceptance; the
only danger is that, as revisions turn into threadbare
commonplaces, the significance of Diarmait will be
explained away. He was—even by the standards of
his time—a ruthless and manipulative ruler, and he
would have had a reputation as such without any
invasion. Recourse to foreign aid may have been nat-
ural step for him. But that should not dilute the fact
that the Anglo-Norman invasion was the single great-
est watershed in Irish history after the conversion of
Ireland to Christianity, and Diarmait Mac Murchada
was central to it.
PETER CROOKS
References and Further Reading
Byrne, F. J. Irish Kings and High-Kings. London: B. T. Bats-
ford, 1973. Reprint, Four Courts Press: Dublin, 2001.
Davies, R. R. Domination and Conquest: The Experience of
Ireland, Scotland and Wales 1100–1300. Cambridge: Cam-
bridge University Press, 1990.
Flanagan, Marie Therese. Irish Society, Anglo-Norman Settlers,
Angevin Kingship: Interactions in Ireland in the late 12th
Century. Oxford: Clarendon Press, 1989.
Gillingham, John. “The English Invasion of Ireland.” In The
English in the Twelfth Century: Imperialism, National Identity
and Political Values. Woodbridge: Boydell and Brewer, 2000.
Giraldus Cambrensis. Expugnatio Hibernica: the Conquest of
Ireland. Edited with translation by A. B. Scott and F. X.
Martin. Royal Irish Academy: Dublin, 1978.
Martin, F. X. “‘No Hero in the House’: Diarmait Mac Murchada
and the Coming of the Normans to Ireland.” O‘Donnell
lecture 19, 1975. Dublin, 1976.
Ó Corráin, Donnchadh. “The Education of Diarmait MacMur-
chada.” Ériu28 (1977): 71–81.
———. “Diarmait MacMurrough (1110–71) and the Coming
of the Anglo-French.” In Wor sted in the Game: Losers in
Irish History, edited by Ciarán Brady. Lilliput Press: Dublin,
1989.
Ó Cuiv, Brian. “Diarmaid na nGall.” Éigse16 (1975): 136–44.
Orpen, G. H., ed. The Song of Dermot and the Earl. Oxford:
Clarendon Press, 1892.
See alsoAnglo-Norman Invasion; Diarmait mac
Máele-na-mbó; Henry II; Leinster; Mac Lochlainn,
Muirchertach; Ua Conchobair, Ruairí; Ua
Conchobair, TairrdelbachMACMURROUGH
a family line of the Uí Chennselaig that held the king-
ship of Leinster from the middle of the 1040s to 1603.
In the 1040s the Uí Chennselaig, under the leadership
of Diarmait mac Máel na mBó (sl. 1072), emerged to
claim the Leinster kingship and challenge for the high
kingship. It was from Diarmait’s son Murchadh that
the later MacMurroughs traced their descent. The
death of Murchad in 1070 and the death of Diarmait
mac Máel na mBó at the battle of Odba in 1072 were
considerable blows, leaving the kingdom of Leinster
vulnerable to Thomond and Connacht. Thereafter the
descendants of Diarmait’s brother Domnall Remar
(sl.1041) tried to monopolize the Leinster kingship.
It was not until 1114, when Donnchad mac Murchada
(sl. 1115) defeated his cousin Máel mórda, that the
MacMurroughs firmly established themselves over
UíChennselaig. This Donnchad, however, had to share
the Leinster kingship with the powerful Conchobar
UaConchobiar (O’Connor Faly) of Offaly (sl. 1115).
Their joint reign was brief, as Domnall Ua Briain and
the Dublin Ostmen routed the pair—burying
Donnchad with a dog in the floor of the Ostman assem-
bly house. The kingship thereafter passed to the short-
lived Diarmait son of Énna MacMurrough (d. 1117)
before Donnchad’s son Énna MacMurrough (d. 1126)
was elected provincial king. Upon his death in 1126,
it appears that he was succeeded by his younger
brother—the famous Diarmait Mac Murchada (d. 1171).
During his early reign, Diarmait’s kingship was dis-
puted by Domnall Mac Fáeláin of Uí Fáeláin (sl. 1141)—
a supporter of Tairrdelbach Ua Conchobair, high king
of Ireland. Mac Fáeláin’s opposition to Diarmait was
finally ended in 1141, allowing the latter to rule unin-
terrupted until 1166. In that year Diarmait was driven
from his kingdom by his enemies—allies of Ruaidrí
Ua Conchobair, high king of Ireland. Diarmait
returned to Ireland in 1167, eventually establishingMAC MURCHADA, DIARMAIT