The Irish surname Brien is an anglicized form of Gaelic Ó Briain meaning “descendant of Brian,” a personal name probably based on the element bre- ‘hill’, with the transferred sense ‘eminence’, i.e. ‘exalted one’. The Brien’s take their name from Brian Boru (941 - 1014), High King of Ireland, who was killed at the Battle of Clontarf. A very powerful and outstanding sept in Irish history, the Brien’s divided into several branches and established themselves throughout Munster. The first recorded spelling of the family name is shown to be that of O'Brien, which was dated circa 1055, in the "Annals of the Four Masters."