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 High King of Ireland.
Sobre a base dos logros do seu pai, Cennétig mac Lorcain, e especialmente do seu irmán maior, Mathgamain, Brian converteuse a si mesmo Rei de Munster, e posteriormente subxugou Leinster, converténdose eventualmente en Rei de toda Irlanda.