Why do so many Irish names begin with “O?
” It reflects a practice found in many cultures: the use of the “patronymic.” Last names originated in the Middle Ages when men, who embodied the continuity of the family, started to be identified by their relationship to their immediate ancestors. The son of David, for example, might take the name Davidson. The Scots used “Mac,” which meant “the son of,” for this purpose. And so with the Irish and the “O’,” except here it meant “the grandson of, ” possibly because one of the first to use it, Teigue, grandson of Brian, High-King of the Irish in the 11th century, started to call himself Ua Briain (Gaelic for O’Brian) after his famous grandfather.
