Brian (926-1014), king of Ireland, known as Brian Boru, Boroma, or Boroimhe (from boroma, an Irish word for tribute), was a son of a certain Kennedy or Cenneide (d. 951). He passed his youth in fighting against the Danes, who were constantly ravaging Munster, the northern part of which district was the home of Brian's tribe, and won much fame in these encounters. In 976 his brother, Mathgamhain or Mahon, who had become king of Thomond about 951 and afterwards king of Munster, was murdered; Brian avenged this deed, became himself king of Munster in 978, and set out upon his career of conquest. He forced the tribes of Munster and then those of Leinster to own his sovereignty, defeated the Danes, who were established around Dublin, in Wicklow, and marched into Dublin, and after several reverses compelled Malachy (Maelsechlainn), the chief king of Ireland, who ruled in Meath, to bow before him in 1002. Connaught was his next objective. Here and also in Ulster he was successful, everywhere he received hostages and tribute, and he was generally recognized as the ardri, or chief king of Ireland. After a period of comparative quiet Brian was again at war with the Danes of Dublin, and on the 23rd of April 1014 his forces gained a great victory over them at Clontarf. After this battle, however, the old king was slain in his tent, and was buried at Armagh. Brian has enjoyed a great and not undeserved reputation.
One of his charters is still preserved in Trinity College, Dublin.
See E.A. D'Alton, History of Ireland, vol. i. (1903).