Brian Boru, Irish king (b. 941)
Brian Boru (Middle Irish: Brian Bóruma mac Cennétig; modern Irish: Brian Bóramha; c. 941 – 23 April 1014) was an Irish king who ended the domination of the High Kingship of Ireland by the Uí Néill and probably ended Viking invasion/domination of Ireland. Brian built on the achievements of his father, Cennétig mac Lorcain, and especially his elder brother, Mathgamain. Brian first made himself king of Munster, then subjugated Leinster, eventually becoming High King of Ireland. He was the founder of the O'Brien dynasty, and is widely regarded as one of the most successful and unifying monarchs in medieval Ireland.
With a population of under 500,000 people, Ireland had over 150 kings, with greater or lesser domains. The Uí Néill king Máel Sechnaill mac Domnaill, abandoned by his northern kinsmen of the Cenél nEógain and Cenél Conaill, acknowledged Brian as High King at Athlone in 1002. In the decade that followed, Brian campaigned against the northern Uí Néill, who refused to accept his claims, against Leinster, where resistance was frequent, and against the Norse-Gaelic Kingdom of Dublin. Brian was described in the Annals of Ulster as ardrí Gaidhel Erenn & Gall & Bretan, August iartair tuaiscirt Eorpa uile (High King of the Gaels of Ireland and the Norse foreigners and the Britons, Augustus of all north-western Europe), the only Irish king to receive that distinction in the annals.Brian's hard-won authority was seriously challenged in 1013 when his ally Máel Sechnaill was attacked by the Cenél nEógain king Flaithbertach Ua Néill, with the Ulstermen as his allies. This was followed by further attacks on Máel Sechnaill by the Germanic Norsemen of Dublin under their Norse king Sigtrygg Silkbeard and the Leinstermen led by Máel Mórda mac Murchada. Brian campaigned against these enemies in 1013. In 1014, Brian's armies confronted the armies of Leinster and Dublin. The resulting Battle of Clontarf saw Brian killed, his army nonetheless victorious against the Leinstermen and Norsemen. The battle is widely lauded as an instrumental moment in Irish history, and is well known in popular memory.
Brian was well regarded by contemporary chroniclers. The Norse-Gaels and Scandinavians also produced works mentioning Brian, including Njal's Saga, the Orkneyinga Saga, and the now-lost Brian's Saga. Brian's war against Máel Mórda and Sigtrygg was to be inextricably connected with his complicated marital relations, in particular his marriage to Gormlaith, Máel Mórda's sister and Sigtrygg's mother, who had been in turn the wife of Amlaíb Cuarán, king of Dublin and York, then of Máel Sechnaill, and finally of Brian himself.