Hi..my GG granfather was Mortimer Sullivan in Brookline, Mass but in Gaelic and in Castletown Bere where he was from and died was Murtagh O'Sullivan. (B-1848-1917) His father was Mortimer O'Sullivan and his mother was Mary. I can't go back any further in my research for his parents. The O'Sullivan name is extremely popular in that area. Are you on ancestry? My tree is public and see if anything matches up? We are of the same surname and the same town so it's a possibility.