Orosius, Paulus - (Catholic Encyclopedia) Offa - (Catholic Encyclopedia) Otranto - (Catholic Encyclopedia) Otho, Marcus Salvius - Details on the reign of Roman Emperor. Oresme, Nicole - Article by Pierre Duhem on this medieval scientific thinker. Osee - The prophet and his book. Occult Art, Occultism - (Catholic Encyclopedia) Ouen, Saint - Seventh-century Archbishop of Rouen, founder of several monasteries, devoted to theological studies, friend of St. Eloi. Odo, Saint - Second abbot of Cluny, died 942. Omer, Saint - Swiss-born bishop of Terouenne in Belgic Gaul, founder of a monastery. He died in about 670. Odilo, Saint - Abbot of Cluny. He died in 1048. Odo, Saint - Benedictine monk, Archbishop of Canterbury, died in 959. Olaf Haraldson, Saint - Martyr and King of Norway, d. 1030. Oswin, Saint - Biography of the king and martyr, who was murdered in 651. Osmund, Saint - A Norman by birth, Osmund became bishop of Salisbury, and died in 1099. Odilia, Saint - Patroness of Alsace, d. 720, founded the convent of Hohenburg. Optatus, Saint - Fairly long essay on the life and writings of this bishop, who argued against the Donatists. He died in about 387. Oswald, Saint - King of Northumbria and martyr, d. 642. Othmar, Saint - First abbot of St. Gall. He died in prison in 759. Olympias, Saint - Widow, deaconess, renowned for her almsgiving, and a staunch supporter of St. John Chrysostom. Oswald, Saint - Archbishop of York, d. 992 while washing the feet of the poor, as was his daily custom during Lent. Odo of Cambrai, Blessed - Benedictine abbot, bishop of Cambrai, exiled for political reasons, d. 1113. Oliver Plunket, Saint - Biographical article on the professor of theology, Archbishop of Armagh and Primate of All Ireland, martyred in 1681. Otto, Saint - Swabian courtier, was named bishop of Bamberg in 1102, and founded over twenty monasteries. Orders, Holy - (Catholic Encyclopedia) Old Catholics - (Catholic Encyclopedia) O'Connell, Daniel - (Catholic Encyclopedia) O'Higgins, Ambrose and Bernard - (Catholic Encyclopedia) Ogdensburg, Diocese of - (Catholic Encyclopedia) Our Lady of the Snow - (Catholic Encyclopedia) O'Braein, Tighernach - (Catholic Encyclopedia) Obedience, Religious - (Catholic Encyclopedia) O'Queely, Malachias - (Catholic Encyclopedia) O'Reilly, Bernard - (Catholic Encyclopedia) Ostensorium (Monstrance) - (Catholic Encyclopedia) O Antiphons - (Catholic Encyclopedia) Oregon City - (Catholic Encyclopedia) Ostrogoths - (Catholic Encyclopedia) Ostracine - (Catholic Encyclopedia) Obedience - (Catholic Encyclopedia) Ontology - (Catholic Encyclopedia) Oran - (Catholic Encyclopedia) Original Sin - (Catholic Encyclopedia) Oriani, Barnaba - (Catholic Encyclopedia) O'Conor, Charles - The son of Irish immigrants, he was an eminent New York lawyer and orator. He defended Jefferson Davis and prosecuted Boss Tweed. Died 1884. Ozias - (Catholic Encyclopedia) Oakeley, Frederick - (Catholic Encyclopedia) O'Devany, Cornelius - (Catholic Encyclopedia) Odin, John Mary - (Catholic Encyclopedia) Odo of Canterbury - (Catholic Encyclopedia) Ostraka, Christian - (Catholic Encyclopedia) O'Cullenan, Gelasius - (Catholic Encyclopedia) Obligation - (Catholic Encyclopedia) Obreption - (Catholic Encyclopedia) O'Bruadair, David - (Catholic Encyclopedia) Olier, Jean-Jacques - (Catholic Encyclopedia) Obba - (Catholic Encyclopedia) Oettingen - (Catholic Encyclopedia) Oggione, Marco D' - (Catholic Encyclopedia) Oria - (Catholic Encyclopedia) Ossat, Arnaud d' - (Catholic Encyclopedia) O'Fihely, Maurice - (Catholic Encyclopedia) Oxford, University of - (Catholic Encyclopedia) O'Dwyer, Joseph - (Catholic Encyclopedia) O Filii et Filiae - (Catholic Encyclopedia) Oertel, John James Maximilian - (Catholic Encyclopedia) O'Herlahy, Thomas - (Catholic Encyclopedia) Ohler, Aloys Karl - (Catholic Encyclopedia) Obazine, Monastery of - (Catholic Encyclopedia) Occasionalism - (Catholic Encyclopedia) Oecumenius - (Catholic Encyclopedia) O'Hussey, Maelbrighte - (Catholic Encyclopedia) Occasions of Sin - (Catholic Encyclopedia) Ojeda, Alonso de - (Catholic Encyclopedia) Oxford Movement, The (1833-1845) - Lengthy historical article on the Tractarian Movement includes information on John Henry Newman, as well as on other leading lights of this nineteenth-century Anglo-Catholic campaign, such as John Keble and Hurrell Froude. Option, Right of - (Catholic Encyclopedia) Olah, Nicolaus - (Catholic Encyclopedia) Old Hall (St. Edmund's College) - (Catholic Encyclopedia) Okeghem, Jean d' - (Catholic Encyclopedia) Oldenburg - (Catholic Encyclopedia) Oecolampadius, John - (Catholic Encyclopedia) Oil of Saints - (Catholic Encyclopedia) Offertory - (Catholic Encyclopedia) Octavarium Romanum - (Catholic Encyclopedia) Omaha, Diocese of - (Catholic Encyclopedia) Oremus - (Catholic Encyclopedia) Ontario - (Catholic Encyclopedia) Ordeals - (Catholic Encyclopedia) Obregonians - (Catholic Encyclopedia) Olivet, Mount - (Catholic Encyclopedia) O'Hurley, Dermond - (Catholic Encyclopedia) Oaths - (Catholic Encyclopedia) O'Hely, Patrick - (Catholic Encyclopedia) Omission - (Catholic Encyclopedia) Oeconomus, Episcopal - (Catholic Encyclopedia) Oblate Sisters of Providence - (Catholic Encyclopedia) Onias - (Catholic Encyclopedia) Optimism - (Catholic Encyclopedia) Old Chapter, The - (Catholic Encyclopedia) Ossory, Diocese of - (Catholic Encyclopedia) Octave - (Catholic Encyclopedia) Ohio - (Catholic Encyclopedia) Ophir - (Catholic Encyclopedia) O'Neill, Hugh - (Catholic Encyclopedia) Oaths, English Post-Reformation - (Catholic Encyclopedia) Our Lady of Good Counsel, Feast of - (Catholic Encyclopedia) Oostacker, Shrine of - (Catholic Encyclopedia) Olympus - (Catholic Encyclopedia) Oates's Plot - (Catholic Encyclopedia) Office of the Dead - Historical article on a special set of prayers for the deceased. Omnipotence - (Catholic Encyclopedia) Oracle - (Catholic Encyclopedia) Ordinariate - (Catholic Encyclopedia) Ontologism - (Catholic Encyclopedia) O'Neill, Owen Roe - (Catholic Encyclopedia) Oregon - (Catholic Encyclopedia) Orate Fratres - (Catholic Encyclopedia) Ointment in Scripture - (Catholic Encyclopedia) Otto of St. Blasien - (Catholic Encyclopedia) Ozanam, Antoine-Frédéric - (Catholic Encyclopedia) O'Brien, Terence Albert - (Catholic Encyclopedia) Olivetans - (Catholic Encyclopedia) Orihuela - (Catholic Encyclopedia) Ostiensis - (Catholic Encyclopedia) O'Loghlen, Michael - (Catholic Encyclopedia) Oriental Study and Research - (Catholic Encyclopedia) Osimo - (Catholic Encyclopedia) Orbellis, Nicolas d' - (Catholic Encyclopedia) Osnabrück, Diocese of - (Catholic Encyclopedia) Oriflamme - (Catholic Encyclopedia) O Salutaris Hostia - (Catholic Encyclopedia) Odense, Ancient See of - (Catholic Encyclopedia) Orans - (Catholic Encyclopedia) Orientation of Churches - (Catholic Encyclopedia) Otfried of Weissenburg - (Catholic Encyclopedia) Oslo, Ancient See of - (Catholic Encyclopedia) Our Lady of the Fields, Brothers of - (Catholic Encyclopedia) Overbeck, Friedrich - (Catholic Encyclopedia) Oaxaca - (Catholic Encyclopedia) Oratory, French Congregation of the - (Catholic Encyclopedia) Our Lady, Help of Christians, Feast of - (Catholic Encyclopedia) Oratory of Saint Philip Neri, The - (Catholic Encyclopedia) Oscott (St. Mary's College) - (Catholic Encyclopedia) Obedientiaries - (Catholic Encyclopedia) O'Sullivan Beare, Philip - (Catholic Encyclopedia) Oxenford, John - (Catholic Encyclopedia) Oblates of Mary Immaculate - (Catholic Encyclopedia) Oblates of Saint Francis de Sales - (Catholic Encyclopedia) Oblati, Oblatae, Oblates - (Catholic Encyclopedia) O'Callaghan, Edmund Bailey - (Catholic Encyclopedia) O'Carolan, Torlogh - (Catholic Encyclopedia) O'Conor, Charles - Called "the Venerable." Eighteenth-century Irish antiquarian. O'Curry, Eugene - (Catholic Encyclopedia) O'Daly, Daniel - (Catholic Encyclopedia) O'Daly, Donogh Mór - (Catholic Encyclopedia) Odescalchi, Carlo - (Catholic Encyclopedia) O Deus Ego Amo Te - (Catholic Encyclopedia) Odington, Walter - (Catholic Encyclopedia) Odo of Cheriton - (Catholic Encyclopedia) Odo of Glanfeuil - (Catholic Encyclopedia) O'Donnell, Edmund - (Catholic Encyclopedia) O'Donovan, John - (Catholic Encyclopedia) O'Dugan, John - (Catholic Encyclopedia) Offerings - (Catholic Encyclopedia) Ogliastra - (Catholic Encyclopedia) O'Growney, Eugene - (Catholic Encyclopedia) O'Hagan, John - (Catholic Encyclopedia) O'Hagan, Thomas - (Catholic Encyclopedia) O'Hanlon, John - (Catholic Encyclopedia) O'Hara, Theodore - (Catholic Encyclopedia) Oklahoma - (Catholic Encyclopedia) Olba - (Catholic Encyclopedia) Oldham, Hugh - (Catholic Encyclopedia) Oldoini, Augustino - (Catholic Encyclopedia) O'Leary, Arthur - (Catholic Encyclopedia) Olenus - (Catholic Encyclopedia) Olesnicki, Zbigniew - (Catholic Encyclopedia) Olinda - (Catholic Encyclopedia) Oliva - (Catholic Encyclopedia) Oliva, Gian Paolo - (Catholic Encyclopedia) Olivaint, Pierre - (Catholic Encyclopedia) Oliver, George - (Catholic Encyclopedia) Olivi, Pierre Jean - (Catholic Encyclopedia) Olivier de la Marche - (Catholic Encyclopedia) Ollé-Laprune, Léon - (Catholic Encyclopedia) Olmütz - (Catholic Encyclopedia) Ombus - (Catholic Encyclopedia) O'Meara, Kathleen - (Catholic Encyclopedia) Oporto - (Catholic Encyclopedia) Oppenordt, Gilles-Marie - (Catholic Encyclopedia) Oppido Mamertina - (Catholic Encyclopedia) Orange, Councils of - (Catholic Encyclopedia) Orange Free State - (Catholic Encyclopedia) Orange River, Vicariate Apostolic of - (Catholic Encyclopedia) Oratorio - (Catholic Encyclopedia) Oratory - (Catholic Encyclopedia) Orcagna - (Catholic Encyclopedia) Orcistus - (Catholic Encyclopedia) Ordericus Vitalis - (Catholic Encyclopedia) Ordinary - (Catholic Encyclopedia) Ordines Romani - (Catholic Encyclopedia) O'Reilly, Edmund (Theologian) - (Catholic Encyclopedia) O'Reilly, Edmund (Archbishop of Armagh) - (Catholic Encyclopedia) O'Reilly, Hugh - (Catholic Encyclopedia) O'Reilly, John Boyle - (Catholic Encyclopedia) O'Reilly, Myles William Patrick - (Catholic Encyclopedia) Orense, Diocese of - (Catholic Encyclopedia) Organ - (Catholic Encyclopedia) Orientius - (Catholic Encyclopedia) Origen and Origenism - Provides a biography and review of his works, as well as commentary on posthumous influences and the Origenistic Crises. Oristano - (Catholic Encyclopedia) Orkneys - (Catholic Encyclopedia) Orlandini, Niccolò - (Catholic Encyclopedia) Orléans, Diocese of - (Catholic Encyclopedia) Orléans, Councils of - (Catholic Encyclopedia) Orley, Barent Van - (Catholic Encyclopedia) Orme, Philibert de l' - (Catholic Encyclopedia) Oropus - (Catholic Encyclopedia) O'Rorke, Patrick Henry - (Catholic Encyclopedia) Orphans and Orphanages - (Catholic Encyclopedia) Orsi, Giuseppe Agostino - (Catholic Encyclopedia) Orsini - (Catholic Encyclopedia) Orsisius - (Catholic Encyclopedia) Ortelius, Abraham - (Catholic Encyclopedia) Orthodox Church - (Catholic Encyclopedia) Orthodoxy - (Catholic Encyclopedia) Orthodoxy, Feast of - (Catholic Encyclopedia) Orthosias - (Catholic Encyclopedia) Ortolano Ferrarese - (Catholic Encyclopedia) Orval - (Catholic Encyclopedia) Orvieto - (Catholic Encyclopedia) Ory, Matthieu - (Catholic Encyclopedia) Osaka - (Catholic Encyclopedia) Osbald - (Catholic Encyclopedia) Osbern - (Catholic Encyclopedia) Osma, Diocese of - (Catholic Encyclopedia) Ostia and Velletri - (Catholic Encyclopedia) Othlo - (Catholic Encyclopedia) Ottawa, Archdiocese of - (Catholic Encyclopedia) Ottawa, University of - (Catholic Encyclopedia) Otto I (the Great) - (Catholic Encyclopedia) Otto II - (Catholic Encyclopedia) Otto III - (Catholic Encyclopedia) Otto IV - (Catholic Encyclopedia) Ottobeuren - (Catholic Encyclopedia) Otto of Freising - (Catholic Encyclopedia) Otto of Passau - (Catholic Encyclopedia) Overberg, Bernhard Heinrich - (Catholic Encyclopedia) Oviedo, Diocese of - (Catholic Encyclopedia) Oxenham, Henry Nutcombe - (Catholic Encyclopedia) Oxford - (Catholic Encyclopedia) Oxyrynchus - (Catholic Encyclopedia) Ozanam, Jacques - (Catholic Encyclopedia)