Ocha, importance of the battle of, 190, 231 Oengus (Aonġus), a Celtic god, 86 Oengus (Aonġus), king of Munster, 128 O'Farrell (Ua Fearġail) territory extended, 336 Ogham alphabet, origin of, 170; inscriptions, range and time of, 173 Ogmios, Ogme (Oġma), a Celtic god, 171 Oileach=Ailech oirchinnea=chairchinnech oireacht=airecht Oirghialla=Airgialla O'Neill, Brian, career of, 328; chosen chief king, 331 O'Neill dynasty, increased power of, 343 Oriel=Airgialla Orosius, Irish writers influenced by, 90, 92-95 Ovoca, curious origin of the name, 139 P "P-Celts" and "Q-Celts," 43, 46 Paganism, survival of, 224 Palæolithic Age not represented in Ireland, 68 Palladius, Saint, mission of, 163 Parthalón, 39, 88 Patrick, Saint, 159; date of his death, 222; Bury's account of, 225 Pelagius, 164 Pentarchy in Irish tradition, 100 Picts, supposed to be Iberians, 41; Ireland and Britain named from, 59; in Ireland and Scotland, 62-65; legendary origin of, 64; in Ireland, 74; in Ulster, 120, 185; earliest mention of, 141; in Connacht, 180; their kingdom in Scotland overthrown, 204; they lose territory in Ulster, 233 Pliny on Ireland, 135 Political system in ancient Ireland, 274-278 Pomponius Mela on Ireland, 134 Poseidonios on Ireland, 133 Pre-Celtic population of Ireland, 73 Pre-Celtic metal workers, 75, 76 Pretani, significance of the name, 59, 62 Primitive races, assumptions regarding, 83 Property in land, 295-299 Ptolemy on Ireland, 136 Q Qreteni, an ancient name for the Picts, 59 R Race, true and false notions of, 1, 2 Racial fusion in Ireland, 229 Red Earl of Ulster, 336 Revolt against Gaelic rule, 80, 119 Rígdamna (ríoġḋaṁna), precise meaning of, 231 Roman empire, collapse of, 158 Roman military system influences Ireland, 150 "Rosnaree," Ros na Ríoġ, battle of, 103 S