A male name. a Celtic name of doubtful etymology, Brian or Bryan has from early times been a favourite in Ireland on account of the legendary hero Brian Boromhe; but it was, during the Middle Ages, equally popular in England, where it was introduced from Brittany at the time of the Norman Conquest. Brian is the name of 2 sub-tenants in Domesday Book, and for several centuries it was a favourite, as the many common surnames derived from it testify (e.g. Brian, Briant, Bryan, Bryant, Briand, Bryanson). It survived in Yorks, Westmorland, Cheshire, Lancs until the 18th C, but gradually fell into disuse and came to be regarded as an exclusively Irish name It is still used in Brittany and has come back into use in England during the present century.

Brienus Domesday Book 1086, Curia Regis Rolls 1199. Brianus Curia Regis Rolls 1199-1219 Brian Hundred Rolls 1273.

BRYAN. literally, ‘strong’ (Celtic, but cognate with Old Norse Brján; the Latin form being Brennus). ‘Brian has from very old times been a favourite... in both Brittany’—as Brien—‘and Ireland, the first no doubt from the Christian honours of (Bran the Blessed), the second from the source whence he was named. The great glory of Brian in Ireland was in the renowed Brian Boromhe’ or Boru (926-1014), who fought twenty-five battles against the Danes, became chief king in Ireland in 1002, and was slain in his tent after his great victory at Clontarf on Good Friday. (Yonge; Harvey.)

BRIANT. Male baptismal names derived from the Irish name Brian, which has been rendered ‘warrior of great strength’ (bri-an). According to some it has been sometimes Anglicised to Bernard.

Celtic and Gaelic (masculine) - Terrible chief.