Brian O'Neill (High-King of Ireland)
| Brian O'Neill | |
|---|---|
| High King of Ireland | |
| Reign | 1258–1260 |
| Predecessor | Rory O'Connor (1166–1198) |
| Successor | None Edward Bruce as claimant (1315–1318) |
| King of Tyrone | |
| Reign | 1238–1260 |
| Predecessor | Donnell Og O'Neill |
| Successor | Hugh Boy O'Neill |
| Died | c. 14 May 1260 near Downpatrick, Ireland |
| Issue | Donnell O'Neill |
| Dynasty | Northern Uí Néill (Cenél nEógain) |
| Father | Niall Roe O'Neill |
| Mother | Nuala Ní Conchobair |
Brian O'Neill, also known as Brian "of the battle of Down" O'Neill (Irish: Brian Chatha an Dúna Ua Néill; died c. 14 May 1260), was the King of Tír Eoghain from 1238 and the High King of Ireland from 1258 to 1260.