(Family name John Poinsot), theologian, born at Lisbon, 9 June, 1589; died at Fraga, Spain, 17 June, 1644. Of noble parentage, he was sent early to the University of Coimbra, displayed talents of the first order, completed his humanities and philosophy, and obtained the degree of Master of Arts. He then entered the University of Louvain. Here, too, he showed remarkable ability, and won the title of Bachelor of Theology at an early age. He joined the Dominicans at Madrid in 1612 or 1613, taking the name of John of St. Thomas, by which he is known to history. As professor of philosophy and theology in a monastery at Alcalá, he soon took rank among the most learned men of the time, and was placed successively (1630 and 1640) in charge of the two principal chairs of theology in the university of that city. His renown drew the largest number of scholars that had ever attended its theological faculties. No man enjoyed a greater reputation in Spain, or was more frequently consulted on points of doctrine and ecclesiastical matters. His theological and philosophical writings, which have gone through many editions, are among the best expositions of St. Thomas's doctrine, of which he is acknowledged to be one of the foremost interpreters. Though he took an active part in the scholastic discussions of his times, his courtesy was such that he is said never to have hurt an opponent's feelings. So faithful was he to the traditions of his order and the principles of the Angelic Doctor that in his last illness he could declare that, in all the thirty years he had devoted to teaching and writing, he had not taught or written anything contrary to St. Thomas. His humility and his devotion to education caused him to refuse many dignities offered him by the Church and his order. In 1643 Philip IV offered him the office of royal confessor, a position which only religious obedience could induce him to accept. His writings comprise: Cursus philosophicus Thomisticus (9 vols.); Cursus Theologici (9 vols.), which is a commentary on the Summa Theologica of St. Thomas; Tractatus de Approbatione, Auctoritate, et Puritate Doctrinae D. Thomae Aquinatis; a Compendium of Christian Doctrine (in Spanish); and a Treatise on a Happy Death (in Spanish), written at the command of Philip IV.
Quétif and Echard, Scriptores Ord. Praed., II (Paris, 1721), 538; Touron, Hommes illustres de l'ordre de St. Dominique, V (Paris, 1749), 248; Hurter, Nomenclator, I (2nd ed., Innsbruck, 1892), 375; Année Dominicaine, II June, 358-365.