O’Connors of Offaly, [8], [65], [76], [82], [92], [121], [122], [136], [194], [301], [323], [370]
— in Connaught, [191], [269], [406]
O’Crean, John, [214]
O’Cullen, Piers, [259]
O’Daly, Geraldine historian, [7]
— bard in Munster, [419]
O’Dempsey, Sir Terence, [357], [358]
O’Devany, Cornelius, Papal Bishop of Down and Connor, 1582-1612, [466]
O’Dogherty, Sir John, chief of Innishowen, [153], [191], [196], [197], [261], [268], [301], [321], [362], [365]
— Cahir, son of the foregoing, [377]