Mac Maghnuis, Mac Maghnusa
Mac MAGHNUIS, Mac MAGHNUSA—V—M'Manish, M'Moenassa, MacManus, MacManis, Manus, Manasses; 'son of Maghnus' (Latin 'Magnus,' a name adopted by the Northmen in honour of Charlemagne—Carolus Magnus—and by them introduced into Ireland, anglicised Manus); the name (1) of a Roscommon family, descended from Maghnus, son of Turlough Mor O'Connor, King of Ireland, who was slain in the year 1181, formerly seated in Tirhoohil; and (2) of a Fermanagh family, descended from Maghnus, son of Donn Maguire, chief of Fermanagh, who died in 1302. The head of this family lived at Senadh Mic Maghnusa, now Belle Isle, in Lough Erne. The name is often pronounced Mac Maonuis, or Mac Maonusa.
Alphabetical Index to Irish Surnames