Brian Boru

Who was Brian Boru?

Brian Boru was an Irish king who ended the domination of the High Kingship of Ireland by the Uí Néill. Building 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 King of All Ireland. He is the founder of the O'Brien dynasty.

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'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 Dubliners under their king Sihtric Silkbeard and the Leinstermen led by Máel Mórda mac Murchada.