I don't know whether the name is English, Irish or German, but I think it's one of those. Anyone know?
(origin Saxon) From Here, a soldier, and beorht, bright--an expert soldier, or the glory of an army; famous in war.
Source: An Etymological Dictionary of Family and Christian Names With an Essay on their Derivation and Import; Arthur, William, M.A.; New York, NY: Sheldon, Blake, Bleeker & CO., 1857.