Irenaeus (late second to early third centuries), saint and Father of the Church. He wrote many works in Greek, of which only a few are extant in their entirety in later Latin translations; the rest survive only in fragments reported by others.
Isidore of Seville (ca. 560-636), saint and bishop of Seville. He wrote a widely popular Etymologiae, an encyclopedic work arranged as a dictionary on several branches of knowledge.
Isidoro from Milan (Isidoro Isolani) (d. 1528), Dominican theologian and pupil of Silvestro Mazzolini da Prierio, prolific author of theological and ecclesiological works, and of the Revocatio Martini Lutheri Augustiniani ad Sanctam sedem, published anonymously in Cremona in 1519.
Ithacius (fourth century), bishop of Ossanoba and opponent of Priscillian.
Ivo of Chartres (ca. 1040-1115), saint and celebrated canonist and theologian. His works include the Decretum and the Panormia, which were the key references for canon law until Gratian.
James VI and I (1566-1625), king of Scotland as James VI, and, from 1603, king of England and Ireland as James I. He promulgated the 1606 Oath of Allegiance and defended it in his own writings, in particular the Triplici nodo, triplex cuneus, to which Bellarmine responded on several occasions.
Jean de Selve (Joannis de Selva) (1475-1520), influential politician and expert on canon and civil law. He was the author of De beneficio (1504), often reprinted during the sixteenth and seventeenth centuries.
Jean Quintin (Haeduus) (ca. 1509-61), professor of canon law at the university of Paris and author of several commentaries on the Corpus iuris canonici.
Jerome (ca. 340-420), saint and Father of the Church. He wrote the Latin translation of the Bible known as Vulgata, which the Council of Trent reasserted as the only allowed version of the Bible. Famously gifted as a linguist, he wrote many commentaries on the Bible and treatises against heresies, especially Pelagianism.
Jerome of Prague (1379-1416), follower of Jan Hus and burned with him at the Council of Constance.
Johannes Andreae (ca. 1270-1348), famous jurist and professor of both canon and civil law in Bologna.
John of Capistrano (1385-1456), saint, Franciscan friar, and author of many ecclesiological and theological treatises, including De auctoritate papae, often referred to by Bellarmine.
John the Deacon (Johannes Hymonides) (ninth century), monk and deacon of the Roman Church, author of a biography of Gregory the Great.
Josephus, Flavius (ca. 37-100), Jewish historian and author of Jewish Antiquities, Jewish War, and Against Apion, all written in Greek.
Jovian (ca. 330-64), Roman emperor, successor of Julian the Apostate.
Julian, Flavius Claudius, “the Apostate” (d. 363), Roman emperor who abandoned the Christian religion and attempted to restore paganism in Rome.
Justinus, Marcus Junianus (third century), Roman historian, author of the Epitoma historiarum Philippicarum.
Karlstadt (Carlstadt) (Andreas Bodenstein) (1486-1541), Protestant reformer and erstwhile collaborator of Luther, who soon disagreed with important Lutheran doctrinal and liturgical points. For example, Karlstadt denied the real presence of Christ in the Eucharist and rejected infant baptism.
Krantz, Albert (ca. 1450-1517), German Catholic historian whose works include the well-known Hamburgenses historiae and Metropolis, sive historia de ecclesiis sub Carolo Magno in Saxonia.
Lambert of Hersfeld (ca. 1024-d. after 1077), Benedictine monk and historian, author of a chronicle of the world from the Creation to the year 1077 and of a history of Germany.
Latomus, Jacobus (Jacques Masson) (1475-1544), professor of theology at Louvain and opponent of Erasmus against whose theology and philological method he wrote De trium linguarum et studii theologici ratione dialogus (1519). He wrote several other theological works against Protestant doctrine and ecclesiology.
Ledesma, Martin (d. ca. 1575), Dominican professor of theology at the University of Coimbra, pupil of Vitoria, and author of an influential commentary on Peter Lombard’s Sententiae.
Leo I (Leo the Great) (d. 461), pope and saint, author of numerous sermons to which Bellarmine often refers.
Leo Ostiensis (Marsicanus) (ca. 1045-1115), Benedictine monk and bishop of Ostia, author of a chronicle of the monastery of Monte Cassino.
Liberatus of Carthage (sixth century), author of an important anti-Nestorian work, Breviarium causae Nestorianorum.
Licinius, Galerius Valerius (ca. 260-325), Roman emperor, defeated by Constantine in 314.
Livy (Titus Livius) (59 B.C.-17 A.D.), one of the most influential Roman historians, thanks to his history of Rome from its foundation to his own days, Ab urbe condita. He was much admired during the Renaissance and subsequently, and the subject of Machiavelli’s Discorsi sopra la prima deca di Tito Livio.
Louis IX (1214-70), king of France and saint, usually known as St. Louis.
Louis the Pious (778-840), king of the Franks and Holy Roman Emperor.
Lucius (second century), semilegendary Christian king of Britain.
Marcellus of Ancyra (fourth century), bishop and great opponent of Arianism.
Marcian (d. 457), Eastern Roman Emperor from 450.
Marcion (second century), founder of the heretical sect of Marcionites. Rejecting the Old Testament, they believed that Jesus was not the son of the God of the ancient Covenant, but of the “good” God of the Gospel.
Marianus Scotus (ca. 1028-ca. 1082), Irish monk and author of a Chronicon covering the period from the beginning of the Christian era until 1082.
Martin of Tours (ca. 316-97), saint, bishop, and vigorous opponent of the Priscillian heresy.
Martinus of Lodi (Garatus) (mid-fifteenth century), professor in Pavia and Siena, author of several treatises on both civil and canon law.
Masson, Jean Papire (Papirius Massonius) (1544-1611), French historian and author of a history of France titled Annales, in four volumes, published in 1578, and a series of biographies of popes, De vitis Episcoporum urbis, censored by Bellarmine in 1592.
Matthew Paris (ca. 1200-ca. 1259), Benedictine monk, author of Chronica maiora, a history of the world from creation to the year of his death.
Mayron, Francis (ca. 1280-1327), Franciscan theologian, pupil of Duns Scotus, author of many theological treatises and a commentary on Peter Lombard’s Sententiae.
Mazzolini da Prierio, Silvestro (Sylvester Prierias) (ca. 1460-1523), Dominican theologian and Master of the Sacred Palace, author of an influential Summa Sylvestrina.
Melanchthon, Philip (1497-1560), one of Luther’s main collaborators and a well-known humanist scholar. He was the author of the Loci communes (1521), commonly considered the first systematic exposition of Lutheran theology. He also drafted the Augsburg Confession of 1530.
Miguel de Aninyon (Aniñón) (d. 1596), professor of law and author of the Tractatus de unitate ovilis et pastoris, published in 1578.
Molina, Luis de (1535-1600), Jesuit and one of the most important and controversial theologians of his day. His works include Concordia liberi arbitrii cum gratiae donis (1588), which stirred the controversy de auxiliis; a commentary on several parts of Aquinas’s Summa; and De iustitia et iure, a classic text of neo-Thomist political and moral theology, only published in full posthumously.
Montserrat, Guillem (late fifteenth century), Catalan jurist and author of a historical work, De successione regum.
Nauclerus, Johannes (ca. 1425-1510), historian and jurist, author of a chronicle covering the period from the Creation to 1500 by generations.