Aqui'nas, THOMAS (or Thomas of Aquino), the prince of scholastic theologians, was of the family of the Counts of Aquino, and was born about 1226 in the castle of Rocca Secca, near Aquino, a small town of 3000 inhabitants, halfway between Rome and Naples. He received the rudiments of his education from the Benedictine monks of Monte-Casino, and completed his studies at the university of Naples. A strong inclination to solitude and the religious life determined him, against the will of his family, to enter (1243) the order of Preaching Friars founded by St Dominic, who had been dead twenty-two years. In order to frustrate the attempts of his mother to remove him from the convent, he was sent away from Naples, first to Rome and then to Paris; but his brothers took him by force from his conductors, and carried him to the paternal castle. Here he was guarded as a prisoner for two years, when, by the help of the Dominicans, he contrived to escape, and went through France to the Dominican convent at Cologne, in order to enjoy the instructions of the famous Albertus Magnus (q.v.). According to another account, he owed his release from confinement to the interference of the emperor and the pope. At Cologne he pursued his studies in such silence, that his companions gave him the name of the 'Dumb Ox.' But Albert is said to have predicted 'that this ox would one day fill the world with his bellowing.' In 1248, being 22 years of age, he was appointed by the general chapter of his order to teach at Cologne, together with his old master, Albert. He now began to publish his first works, commentaries on the ethics and the philosophy of Aristotle. In 1252 he was sent to Paris. His masterly application of this philosophy to the systematising of theology, soon procured him a distinguished reputation. It was not, however, till 1257 that Aquinas and his friend St Bonaventura, the Franciscan, obtained their degree of doctor, as the university of Paris, under the influence of William de St Amour, was hostile to the mendicant friars. He vindicated the principles of these orders in an important work; and, in a disputation in presence of the pope, procured the condemnation of the books of his adversaries. He continued to lecture with great applause in Paris, till Urban IV. in 1261 called him to Italy to teach in Rome, Bologna, and Pisa. It was at this time he composed most of his great works.
Even during his life Aquinas enjoyed the highest consideration in the church. His voice carried decisive weight with it; and his scholars called him the 'Angel of the Schools' or 'Angelic Doctor.' A general chapter of Dominicans in Paris made it obligatory on the members of the order to defend his doctrines. Both Urban IV. and his successor, Clement IV., were much attached to Aquinas, pressed upon him the highest ecclesiastical dignities in vain. So great was his modesty, and his love of poverty and study, that he refused the archbishopric of Naples.
Like most of the other scholastic theologians, he had no knowledge of Greek or Hebrew, and was almost equally ignorant of history; but his numerous writings display an intellectual power of the highest order. He gave a new and scientific foundation to many doctrines of his church, especially that of transubstantiation. He also treated Christian morals according to an arrangement of his own, and with a comprehensiveness that procured him the title of the 'Father of Moral Philosophy.' The definiteness, clearness, and completeness of his method of handling theology were such that his Summa Theologie, which may be said to be the first attempt at a complete theo- gical system, remains to this day substantially the standard authority in the Roman Church. Another important work of Aquinas is his Summa contra Gentiles, which deals chiefly with the principles of natural religion. His commentaries on Scripture and devotional treatises also have a high reputation. His influence on the theological thought of succeeding ages was immense. At the council of Trent, the Summa was honoured with a place on the table by the side of the Bible. It was at Bologna that he began this his greatest work, by which his name will always be connected, but which he never lived to complete. A legend tells how, when engaged in fervent prayer regarding this book, he heard the words from his crucifix: 'Thou hast written well of me, Thomas: what reward dost thou ask?' and he answered, 'None other but Thyself, O Lord.' On December 6, 1273, he was writing at Naples the 90th question of the third part of the Summa, when weakness of health compelled him to break off his studies. But Gregory X., who had called a general council to effect the union of the Greek and Latin churches, summoned Aquinas to defend the papal cause at Lyons, where the council was to meet on May 1, 1274. He set out, though suffering from fever, and was surprised by death on the road at the Cistercian abbey of Fossa-Nuova, March 7, 1274. All Europe mourned his loss. Miracles were said to be wrought at his funeral. Universities, religious orders, and princes contended for the honour of possessing his body. It was finally bestowed by the pope on Toulouse, where it was received by 150,000 persons headed by Louis, Duke of Anjou. Aquinas was canonised by John XXII. in 1323, and proclaimed a 'Doctor of the Church' by Pius V. in 1567.
The only scholastic theologian who in any degree rivalled Aquinas in his own age, was the so-called 'Subtle Doctor,' Duns Scotus, of the order of St Francis. The Franciscans naturally followed Scotus, and the Dominicans Thomas, and henceforward medieval theologians were divided into two schools, Scotists and Thomists. The divergencies which penetrate more or less every branch of doctrine depend upon the different systems of metaphysics or scholastic philosophy upon which the theologies were based. The differences concerned the idea of God, the operations of grace and of justification, the mode in which the sacraments take effect, &c. Popularly, Scotism is best known for its advocacy of the Immaculate Conception of Mary, and for the doctrine, with which it is remotely connected, that the Incarnation would have taken place (though of course without suffering or death) if Adam had not sinned. The more recondite peculiarities of Scotist theology and philosophy are now almost entirely confined to the theologians of the Franciscan order. On the other hand, Thomism represents, with few exceptions, the general teaching of the Catholic Church. The school is now not so much opposed by the Scotists as by the eclectic school of Jesuit theology. The first complete edition of Aquinas's works was published in 17 vols. folio at Rome in 1570. They have been frequently reprinted, the latest and best edition having been begun in 1883 under the auspices of Leo XIII. The most convenient edition of the Summa is that of Migne (4 vols.). St Thomas was the author of the famous Pange Lingua (q.v.), and other eucharistic hymns of the Roman Breviary. See the Life of St Thomas of Aquin, by the Very Rev. R. B. Vaughan, O.S.B. (2 vols. 1872); and works by Otten (Paderborn, 1882), Lecoutre (Par. 1883), and Eucken (Halle, 1886).