About Brian O'Neill
Lived 1220 – 1260 (aged 39–40). Brian O'Neill was a sovereign.
Brian O'Neill, also known as Brian "of the battle of Down" O'Neill (; died ), was the King of Tír Eoghain from 1238 and the High King of Ireland from 1258 to 1260.
Rise to power In 1230 Hugh O'Neill (Aedh Ó Néill), king of Tyrone, died and was succeeded by Donnell MacLaughlin. his claim was not recognised by those of the Irish closest to him including the other O'Neill factions, the O'Donnells of Tyrconnell, the MacMahons of Airgíalla, and the O'Rourkes of Breifne.
In the battle, O'Neill was killed along with many other Irish nobles including over a dozen members of the O'Cahans. O'Neill's head was cut off by the Normans and sent to King Henry III of England, a sign of how dangerous his coalition was thought to be.
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Important facts
Family & relationships
Related people
Same field, nearest in time
Contemporaries
People whose lives overlapped Brian O'Neill's
Frequently asked questions
Who was Brian O'Neill?
King of Tir Eoghain
When was Brian O'Neill born?
Brian O'Neill was born in 1220.
When did Brian O'Neill die?
Brian O'Neill died on 16 May 1260.
What was Brian O'Neill's occupation?
Brian O'Neill was a sovereign.
Sources & further reading
· DBpedia: Brian O'Neill (High-King of Ireland)
Cite this page
APA: Biography.guide. (2026). Brian O'Neill. https://biography.guide/brian-o-neill-sovereign/
MLA: "Brian O'Neill." Biography.guide, https://biography.guide/brian-o-neill-sovereign/.
Chicago: "Brian O'Neill." Biography.guide. https://biography.guide/brian-o-neill-sovereign/.
Data last updated: 2026-09-20 · Spot an error? Report a correction.
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