Brian (m) The first part of this name is Celtic and signifies 'hill'.
Brian has always been popular in Ireland. It was the name of the most famous of Irish high kings, Brian Boru (reigned 1002-14), the victor of the decisive Battle of Clontarf which put paid to any Norse hopes for the conquest of Ireland. Brian was also the name of the Co. Clare poet, Brian Merriman (c.1757-1808), whose extraordinary work, Cúirt an Mheadhoin Oidhche is an early advocation of the emancipation of women.

A more recent Irish writer was Brian O'Nolan (1911-66) who wrote under the pseudonyms 'Flann O'Brien' and 'Myles na Gopaleen'. The name was also known in medieval Brittany, and it was introduced into England from there. Surnames derived from it include Brian, Brien, Bryan, O'Brien and O'Byrne. Bernard and Barnaby were used to anglicise it.

The name remains widespread in Ireland. It has been revived in England, and is quite common in the United States and Canada. It is found in Italy as Briano. Bryan, Brion and Bryant are variants.