[Ir., old, ancient, enduring].
A name borne by several figures in early Irish narratives, most notably the Connacht warrior in the Ulster Cycle whose patronymic is variously given as mac Mágu, mac Mágach, mac Maga, mac Matach, etc. In Scéla Mucce meic Da Thó [The Story of Mac Da Thó's Pig], he shames the Ulstermen by reminding them of how he has bested them in combat, emasculating Celtchair, etc. He appears to be most deserving of the hero's portion until Conall Cernach arrives. On another occasion he throws the calcified ‘brain ball’ of Mesgegra at Conchobar mac Nessa, severely wounding him. Cet himself was killed by Conall Cernach. Later rulers of Connacht claimed descent from Cet in genealogies.