I

Ian Theodor Beelen	Exegete and Orientalist (1807-1884)
Ibar, Saint	A pre-Patrician Irish saint, who labored in the present County Wexford from 425 to 450
Ibas	Bishop, d. 457
Ibora	Titular see in the Province of Helenopont, suffragan of Amasia
Iceland	Treatment of the country of Iceland
Iconium	A titular see of Lycaonia
Iconoclasm	Heresy opposed to the use of religious images
Iconostasis	Icon-bearing screen in front of the altar in Eastern churches
Ida Hahn-Hahn	Countess, convert and authoress, born June 22, 1805; died January 12, 1880
Idaho	Informtation on the American state
Idea	Treatment of the concept, particularly in philosophy
Idealism	The fairer, nobler, more perfect 'type' than is found in reality.
Idiota	The nom de plume of an ancient, learned, and pious writer whose identity remained unknown for some centuries
Idolatry	The sin of giving divine worship given to an image or to anything other than God
Idumea	The country inhabited by the descendants of Edom
Ignace Bourget	Bishop of Montreal (1799-1885)
Ignace- Gaston Pardies	French scientist, b. at Pau, Sept. 5, 1636; d. of fever contracted whilst ministering to the prisoners of Bicetre, near Paris, April 22, 1673
Ignacio Barbosa-Machado	Portuguese historian (1686-1734)
Ignacio de Arbieto	Jesuit (1585-1676)
Ignacio de Azevedo	B. at Oporto, Portugal, 1528; d. near Palma, one of the Canary Islands, July 15, 1570
Ignacio de Iriarte	Painter (1620-1685)
Ignatius Carbonnelle	Professor of mathematics and science and editor; b. at Tournai, Belgium, 1 Feb. 1829; d. at Brussels, March 4, 1889
Ignatius Knoblecher	Catholic missionary in Central Africa (1819-1858)
Ignatius Krasicki	Canon (1735-1801)
Ignatius Loyola, Saint	Founder of the Jesuits, b. in 1491; d. 1556
Ignatius Mrak	Second Bishop of Marquette, U.S.A., b. October 16, 1818, in Austria; d. at Marquette, Jan. 2, 1901
Ignatius of Antioch, Saint	B. in Syria, c. the year 50; d. at Rome between 98 and 117
Ignatius of Constantinople, Saint	B. about 799; d. October 23, 877
Ignatius Persico	Cardinal, b. Jan. 30, 1823, at Naples, Italy; d. Dec. 7, 1896
Ignatius von Weitenauer	Litterateur, exegete, and Orientalist, b. at Ingolstadt, Bavaria, Nov. 1,1709; d. at Salem near Constance, Wurtemberg, Feb. 4, 1783
Ignaz Assmayer	Austrian musician (1790-1862)
Ignaz Heinrich von Wessenberg	Vicar-General and Administrator of the Diocese of Constance, b. at Dresden, November 4, 1774; d. at Constance, August 9, 1860
Ignaz Kogler	German Jesuit missionary (1680-1746)
Ignaz Philipp Semmelweis	Physician and discoverer of the cause of puerperal fever, b. at Ofen, July 1, 1818; d. at Vienna, August 13, 1865
Ignazio Danti	Mathematician and cosmographer, b. at Perugia, Italy, 1537; d. at Alatri, Oct. 19, 1586
Ignorance	Lack of knowledge about a thing in a being capable of knowing
IHS	A monogram of the name of Jesus Christ
Il Tintoretto	Jacopo Robusti, Italian painter, b. 1518; d. 1594
Ildephonsus, Saint	Archbishop of Toledo; d. January 23, 667
Illegitimacy	The condition of children born out of wedlock

Illinois	Treatment of the American state
Illinois Indians	Treatment of the Algonquian tribes
Illtyd, Saint	Flourished in the latter part of the fifth and beginning of the sixth century
Illuminated Manuscripts	Manuscripts covered with painted illustrations
Illuminati	The name assumed by the members of a secret society founded by Adam Weishaupt in 1776
Illuminati (Alumbrados)	The name assumed by some false mystics who appeared in Spain in the sixteenth century and claimed to have direct intercourse with God
Illyria	A district of the Balkan Peninsula
Imagination	Treatment of the nature and operation of imagination
Imitation of Christ	A work of spiritual devotion by Thomas a Kempis
Immaculate Conception	Treatment of the doctrine
Immaculate Conception (Groups connected with)	Treatment of several groups naming themselves after the Immaculate Conception
Immanence	Treatment of the philosophical concept
Immortality	Doctrine that the human soul will survive death
Immunity	An exemption from a legal obligation
Impanation	Heretical doctrine according to which Christ is in the Eucharist through His human body substantially united with the substances of bread and wine
Impediment of Crime	Nullifies marriage according to ecclesiastical law, and arises from adultery and homicide separately or together
Imposition of Hands	Symbolical ceremony by which one intends to communicate to another some favor, quality or excellence (principally of a spiritual kind), or to depute another to some office
Impostors	Treatment of a number of objectionable characters not of sufficient importance to claim separate treatment
Improperia	Reproaches which in the liturgy of the Office of Good Friday the Savior is made to utter against the Jews
In Coena Domini	Papal Bull, so called from the feast on which it was annually published in Rome
In Commendam	A phrase used in canon law to designate a certain manner of collating an ecclesiastical benefice
In Partibus Infidelium	Term meaning in the lands of the unbelievers
In Petto	Term applied to cardinals appointed by the pope but not publicly announced
Incardination and Excardination	Ecclesiastical terms denoting a person's transfer from the jurisdiction of one bishop to another
Incarnation	Treatment of the doctrine
Incense	Aromatic substance which is obtained from certain resinous trees and burned for purposes of religious worship
Incest	Sexual intercourse between those who are related by blood or marriage
Index of Prohibited Books	List or catalogue of books, the reading of which is forbidden to Catholics
India	India
Indiana	Treatment of the American state
Indifferent Acts	Human acts whose object is morally neither good nor bad
Individual	Treatment of the philosophical concept of individuality
Individualism	Treatment of the sociological concept
Indo-China	The most easterly of the three great peninsulas of Southern Asia
Induction	The conscious mental process by which we pass from the perception of particular phenomena (things and events) to the knowledge of general truths
Indulgences	Treatment of the practice of granting indulgences
Industrial Conciliation	The discussion and adjustment of mutual differences by employers and employees or their representatives
Ine, Saint	King of the West Saxons, d. 728
Infallibility	Treatment of the role of infallibility in the Church
Infamy	Loss of a good name

Infanticide	Killing of an infant before or after birth
Infidels	Those who do not have faith
Infinity	Treatment of the philosophical and theological concept
Infralapsarians	Party of Dutch Calvinists in the seventeenth century, who sought to mitigate the rigor of Calvin's doctrine concerning absolute predestination
Ingres, Jean-Auguste Dominique	A French painter, b. at Montauban, August 29, 1780; d. at Paris, January 14, 1867
Ingulf	Abbot of Croyland, d. December 17, 1109
Inigo Jones	English architect (1573-1652)
Injustice	Violation of another's strict right against his reasonable will
Innocentius, Saints	Name of several saints
Innocenzo di Pietro Francucci da Imola	Italian painter; b. at Imola, c. 1494; d. at Bologna, c. 1550
Innsbruck University	Originated in the college opened at Innsbruck in 1562 by Blessed Peter Canisius
Inquisition	Ecclesiastical institution for combating or suppressing heresy
Insanity	Treatment of the psychological concept
Inscription of Abercius	Inscription of Abercius
Inscriptions, Early Christian	Treatment of the historical value of inscriptions made by early Christians on various objects
Inspiration of the Bible	Treatment of the nature and extent of the inspiration of Scripture
Installation	Symbolic act by which a canon is put in possession of the functions which he exercises in the chapter, and by which the chapter admits him
Instinct	Treatment of the concept of instinct in humans and animals
Institute of Bon Secours de Paris	Congregation of nursing sisters founded in France in nineteenth century
Institute of Mary	Title of the second congregation founded by Mary Ward
Institute of Mission Helpers of the Sacred Heart	Organization promiting the evangelization and assistance of various groups
Institute of Sisters of the Holy Humility of Mary	Founded at Dommartin-sous-Amance, France, in 1855, by John Joseph Begel
Institute of the Brigidines	Established by Most Rev. Dr. Delany, Bishop of Kildare and Leighlin, at Tullow, Co. Carlow, Ireland, in 1807
Institute of the Brothers of the Christian Schools	Lay institute for promoting holiness and Christian education
Institute of the Divine Compassion	Founded in the City of New York, U.S.A., by the Rt. Rev. Thomas Stanislaus Preston
Intellect	Treatment of the faculty of thought
Intention	Act of the will by which that faculty efficaciously desires to reach an end by employing certain means
Intercession	To go or come between two parties to plead before one of them on behalf of the other
Interdict	A form of ecclesiastical censure
Interest	Treatment of the psychological concept
Interest (monetary)	Treatment of the economic concept
Interims	Temporary settlements in matters of religion, entered into by Emperor Charles V with Protestants
International Law	Rules which determine the conduct of the general body of civilized states in their dealings with each other
Internuncio	Name given in the Roman Curia to certain diplomatic agents
Interpretation of Dreams	Something mysterious which seems, from the earliest times, to have impressed man and aroused his curiosity
Introit	Fragment of a psalm with its antiphon sung while the celebrant and ministers enter the church and approach the altar at Mass
Intrusion	Act by which unlawful possession of an ecclesiastical benefice is taken
Intuition	Designates the process of immediate apprehension or perception of an actual fact, being, or relation between two terms, and its results
Inventory of Church Property	A descriptive list in which ecclesial properties are enumerated systematically, item by item
Invitatorium	The invitation addressed to the faithful to come and take part in the Divine Office

Ionian Islands	Group of seven islands in Ionian Sea
Ionian School of Philosophy	Early Greek philosophers
Ionopolis	Titular see in the province of Paphlagonia
Iowa	North Central State in United States
Ippolito Galantini, Blessed	Founder of the Congregation of Christian Doctrine of Florence, Italy
Ippolito Pindemonte	Italian poet of noble birth, b. at Verona, Nov. 13, 1753; d. there, Nov. 18, 1828
Ipsus	Titular see of Phrygia Salutaris
Ireland	Island country in the Atlantic Ocean near Great Britain
Irenaeus, Saint	Bishop of Lyons, Father of the Church (second century)
Irenopolis	Titular see of Isauria
Irish College in Rome	Founded in sixteenth century by Pope Gregory XIII
Irish Colleges on the Continent	Religious school on European continent for Irish clergy
Irish Confessors and Martyrs	Some victims of religious persecution in Ireland begun under Henry VIII (1540) through (approximately) 1713.
Irish diaspora	The Irish in countries other than Ireland
Irish Institute of the Blessed Virgin Mary	Institute founded by Frances Mary Teresa Ball
Irish literature	Literature of Ireland
Irnerius	Italian jurist and founder of the School of Glossators (ca. 1050 - ca. 1130)
Iroquois	A confederation of 5, and later 6, cognate tribes originally in central New York
Irregularity	A quality of certain ecclesiastical offices and dignities
Irremovability	A quality of certain ecclesiastical offices and dignities
Irvingites	Religious sect named for Edward Irving (1792-1834), a deposed Presbyterian minister
Isaac (Old Testament)	Son of Abraham and Sara
Isaac Austin Henderson	B. at Brooklyn, 1850; d. in Rome, March, 1909
Isaac Jogues	French missionary, North American martyr (1607-1648)
Isaac of Armenia	Otherwise known as Isaac the Great (388-439)
Isaac of Nineveh	Nestorian bishop of that city in the latter half of the seventh century
Isaac of Seleucia	Patriarch of the Persian Church (d. 410)
Isaac Thomas Hecker	Missionary, author, founder of the Paulists; b. in New York, December 18, 1819; d. there, Dec. 22, 1888
Isaac-Joseph Berruyer	Jesuit historian (1681-1758)
Isabel of France, Blessed	Daughter of Louis VIII; sister of King St. Louis IX (1225-1270)
Isabella I	Queen of Castile, Spain; called Isabella the Catholic (1451-1504)
Isaias	Old Testament prophet, also called Isaiah
Isaura	Titular see in the province of Lycaonia
Ishmael	Son of Abraham and Hagar
Isidore of Pelusium, Saint	Monk, opposed Nestorianism and Eutychianism (d. ca. 450)
Isidore of Seville, Saint	Last of the ancient Christian philosophers, as he was the last of the great Latin Fathers.
Isidore of Thessalonica	Cardinal and sometime Metropolitan of Kiev or Moscow (d. 1463)
Isidore the Laborer, Saint	Spanish day-laborer (ca. 1070-1130)
Isionda	Titular see in the province of Pamphylia Secunda
Islam	The religion of Muhammad and of the Qur'an

Isleta Pueblo	Two pueblos of the ancient Tigua tribe
Ispahan	Catholic Armenian Latin see
Israelites	Descendants of the Patriarch Jacob (Israel)
Issachar	Ninth son of Jacob and name of the tribe descended from him
Issus	Titular see of Cilicia Prima
Ita, Saint	Irish nun, called 'Brigid of Munster' (ca. 475-570)
Italian literature	Literature of Italy
Italians in the United States	From Christopher Columbus onward
Italo-Greeks	Name applied to the Greeks in Italy who observe the Byzantine Rite
Italy	European country
Ite Missa Est	Chanted in the Roman Rite by the deacon at the end of Mass, after the Post-Communions
Itineraria	Medieval Christian guidebooks
Itinerarium	Form of prayer used by monks and clerics before setting out on a journey
Ivan Sergejewitch Gagarin	Of the princely Russian family which traces its origin to the ancient rulers of Starodub, b. at Moscow, Aug. 1, 1814; d. at Paris, July 19, 1882
Ives, Saint	French (1253-1303)
Ivo of Chartres, Saint	Canonist, notable French bishop during Investiture struggles (d. 1116)
Ivory	Material derived from animal tusks and teeth

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z