Selected Catholic Religious Leaders
- Ãlfric, English writer and Benedictine monk
- Abbo of Fleury, French monk at the abbey of Fleury
- Absalon, Danish churchman, archbishop of Lund
- Adalbert, German churchman
- Ademar, French prelate
- Ailly, Pierre d', French theologian and writer
- Alcuin, English churchman and educator
- Aleksy II, Russian Orthodox clergyman
- Allouez, Claude Jean, French Jesuit missionary in Canada and the American Midwest
- Amyot or Amiot, Joseph, French Roman Catholic missionary in China
- Anchieta, José de, Brazilian Jesuit missionary
- André, Brother, Canadian Roman Catholic mystic
- Antoine, Père, Spanish priest in New Orleans
- Aresson, Areson, or Arason, Jon, Icelandic churchman
- Arius, Libyan theologian, founder of the Arian heresy
- Arnauld, rench family involved in Jansenism
- Arnold of Brescia, Italian monk and reformer
- Aymer of Valence, Bishop of Winchester
- Baraga, Frederic, Roman Catholic missionary to the Native Americans of Upper Michigan
- Barberini, Francesco, Italian prelate and Orientalist
- Bar-Hebraeus, Gregorius, Syrian scholar
- Baronius, Caesar, Italian ecclesiastical historian
- Bartholomew I, Orthodox patriarch of Constantinople
- Beaton or Bethune, David, Scottish churchman
- Bembo, Pietro, Italian humanist
- Berdyaev, Nicholas, Russian theologian and religious philosopher
- Berengar of Tours, French theologian
- Bessarion, Byzantine humanist
- Biard, Pierre, French Jesuit missionary
- Bossuet, Jacques Bénigne, French prelate
- Butler, Alban, English Roman Catholic priest
- Cajetan, Italian prelate
- Campeggio, Lorenzo, Italian churchman and diplomat, cardinal of the Roman Catholic Church
- Capgrave, John, English author and Augustinian friar
- Carpini, Giovanni de Piano, Italian traveler and Franciscan monk
- Carroll, John, American Roman Catholic churchman
- Cassian, John, an Eastern Christian monk and theologian who brought Eastern spirituality to the West
- Challoner, Richard, English Roman Catholic prelate
- Charlevoix, Pierre François Xavier de, French Jesuit traveler and historian
- Charron, Pierre, French Roman Catholic theologian and philosopher
- Chaumonot, Joseph Marie, French Jesuit missionary to the New World
- Cheverus, Jean Louis Anne Madeleine Lefebvre de, French churchman
- Clement of Alexandria, Greek theologian
- Cressy, Hugh Paulinus, English Benedictine monk
- Dablon, Claude, French Jesuit missionary in North America
- Damien, Father, Belgian missionary priest
- David, John Baptist Mary, French missionary in the United States
- De Smet, Pierre Jean, Jesuit missionary in the U.S. Pacific Northwest
- Didon, Henri, French Dominican preacher and writer
- Dollier de Casson, François, priest and explorer in Canada
- Duchesne, Louis Marie Olivier, French Roman Catholic ecclesiastic
- Eck, Johann Maier von, German Roman Catholic theologian
- Eckhart, Meister, German mystical theologian
- England, John, Irish Roman Catholic churchman in America
- Eusebius of Caesarea, Greek apologist and church historian
- Eusebius of Nicomedia, Christian churchman and theologian
- Eutyches, archimandrite in Constantinople
- Faber, Frederick William, English theologian and hymn writer
- Fenwick, Edward Dominic, American Roman Catholic prelate
- Fleury, Claude, French ecclesiastical historian
- Fonseca, Juan RodrÃguez de, Spanish prelate. Chaplain to Isabella and Ferdinand
- Foucauld, Charles, vicomte de, French priest and missionary in the Sahara
- Gallitzin, Demetrius Augustine, American frontier missionary;
- Gasparri, Pietro, Italian churchman
- Gerson, John, French ecclesiastical statesman and writer
- Grégoire, Henri, French priest
- Gratian, Italian legal scholar
- Groote, Gerard or Geert, Dutch Roman Catholic reformer
- Grosseteste, Robert, English prelate
- Hügel, Friedrich, Baron von, British Roman Catholic religious writer
- Harnack, Adolf von, German theologian and church historian
- Hecker, Isaac Thomas, American Roman Catholic priest
- Hergenröther, Joseph Adam Gustav, German theologian and scholar
- Hildebert of Lavardin, French churchman, bishop of Le Mans
- Hincmar, Frankish canonist and theologian
- Hughes, John Joseph, American Roman Catholic churchman
- Ireland, John, American Roman Catholic prelate
- Jacobus da Varagine, Italian hagiographer
- Jansen, Cornelis, Dutch Roman Catholic theologian
- Juliana of Norwich, English mystics
- Kenrick, Francis Patrick, American Roman Catholic churchman
- Lacombe, Albert, French Canadian Roman Catholic missionary
- Lacordaire, Jean Baptiste Henri, French Roman Catholic preacher and liberal
- Lactantius, Lucius Caelius Firmianus, Christian author and apologist
- Lainez, Diego, Spanish theologian
- Lamennais or La Mennais, Félicité Robert de, French Roman Catholic apologist and liberal
- Lamy, Jean Baptiste, Roman Catholic archbishop in the U.S. Southwest
- Lanfranc, Italian churchman and theologian, archbishop of Canterbury
- Langton, Stephen, English prelate, cardinal of the Roman Catholic Church
- Lathrop, Rose Hawthorne, American nun
- Laval, François Xavier de, French prelate in Canada
- Lavigerie, Charles Martial Allemand, French churchman
- Lefèvre d'Ãtaples, Jacques, French theologian and humanist
- Loisy, Alfred Firmin, French theologian
- Mabillon, Jean, French scholar
- Machebeuf, Joseph Projectus, French missionary in the American Southwest
- Manning, Henry Edward, English churchman
- Marcion, early Christian bishop, founder of the Marcionites
- Marie de l'Incarnation, French missionary
- Mazzuchelli, Samuel Charles, Italian missionary in America
- Mercier, Désiré Joseph, Belgian churchman
- Merton, Thomas, American religious writer and poet
- Migne, Jacques Paul, French publisher of theological works
- Milic of Kremsier, Bohemian reformer
- Molay, Jacques de, last grand master of the Knights Templars
- Molina, Luis, Spanish Jesuit theologian
- Newman, John Henry, English churchman, cardinal of the Roman Catholic Church
- Nicole, Pierre, French Jansenist writer
- Nikon, Russian churchman
- Orosius, Paulus, Iberian priest, theologian, and historian
- Ozanam, Antoine Frédéric, French Roman Catholic scholar
- Pandulf, Italian churchman
- Papias, early Christian theologian
- Petavius, Dionysius, French Jesuit theologian and philologist
- Peter Lombard, Italian theologian
- Photius, Greek churchman and theologian, patriarch of Constantinople
- Pire, Georges Henri, Belgian priest
- Rabanus Maurus Magnentius, German scholar and theologian
- Rancé, Armand Jean le Bouthillier de, French religious reformer
- Richard of Saint Victor, Scottish monk and mystic
- Rolle of Hampole, Richard, English religious writer
- Rosmini-Serbati, Antonio, Italian theologian
- Ruysbroeck, John, Roman Catholic mystic
- Sabellius, Christian priest and theologian
- Salvian, Christian writer of Gaul
- Savonarola, Girolamo, Italian religious reformer
- Serra, JunÃpero, Spanish Franciscan missionary in North America
- Servetus, Michael, Spanish theologian and physician
- Sheen, Fulton John, American Roman Catholic clergyman
- Spellman, Francis Joseph, American Roman Catholic cardinal
- Stepinac, Aloysius, Yugoslav prelate
- Suárez, Francisco, Spanish Jesuit philosopher
- Suso, Heinrich, German mystic
- Tauler, Johannes, German mystic
- Teresa, Mother, Roman Catholic missionary in India
- Tertullian, Roman theologian and Christian apologist
- Tetzel, Johann, German preacher
- Theodore of Mopsuestia, Syrian Christian theologian, bishop
- Thomas à Kempis, German monk
- Tunstall or Tonstall, Cuthbert, English bishop
- Ulfilas, Gothic bishop
- Vaughan, Herbert, English churchman
- Vieira, Antonio, Portuguese Jesuit orator and missionary
- Vincent of Beauvais, French Dominican friar
- Ward, William George, English Roman Catholic apologist
- Wiseman, Nicholas Patrick Stephen, English prelate
- Zumárraga, Juan de, Spanish churchman