A very popular name, of uncertain derivation. Until the 20th century it was confined mainly to Scotland and Ireland. It is probably of Scandinavian rather than Celtic origin, however: a short form of any of the various compound names derived from Old Norse brand ‘sword’. Its popularity in Gaelic-speaking countries has no doubt been influenced by its similarity to Brendan.
German and French: from a Germanic personal name composed of the elements helfe ‘help’ + rīc ‘power’, ‘rule’. One of the early medieval kings of the Franks bore this name, in the form Chilperic, and Helferich was also the name of a character in a medieval heroic epic.