Oath by the elements, [25], [28], [88]
O'Briens, the, of Thomond, [35], [64], [452], [493], [518]
O'Brien, Turlough, exploits of, [470]; see "[Caithréim]"
O'Brien Donough, earl of Thomond, hangs three poets, [493]
O'Brien Donough, fourth earl, [515], [518]
O'Brien, Turlough, poet, [516]
O'Brien, Murrough, [569]
O'Brien, Father E., theory on St. Patrick, [137]
O'Brien, Patrick, Irish printer, [601-2]