Aquinas: The Universal Doctor

“Among the Scholastic Doctors, the chief and master of all towers Thomas Aquinas . . . he is rightly and deservedly esteemed the special bulwark and glory of the Catholic faith.”

—Pope Leo XIII, Aeterni Patris

We’ve all heard the name Thomas Aquinas, but who really was this great saint?

As a student he may have been called the Dumb Ox, but Aquinas has become one of the most respected and trusted theologians of all time. His writings have guided the Church in her doctrines since the thirteenth century, while his poetry has given the Church two of her most beautiful hymns of praise to the Blessed Sacrament: Tantum Ergo Sacramentum and O Salutaris Hostia.

Pope Pius V declared Aquinas a Doctor of the Church in 1567, indicating that his teachings are a guide for the Church in all ages and that his thought has largely shaped the Church’s teaching or understanding of certain areas of the faith. Aquinas has the distinction of being considered the Universal Doctor—meaning his writings have touched all areas of Catholic doctrine.

So, who is the man that can be called the bulwark and glory of the Catholic faith?

For the next six weeks, we’ll explore who Thomas Aquinas really was, how he impacted the Catholic Church, and, ultimately, how he changed the world.


Thomas Aquinas, Part I: A Life 

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Born in 1225 at Roccasecca, near Aquino, in the kingdom of Naples, Thomas was the youngest son of Landolfo d’Aquino, the head of a large and aristocratic family. At the age of five he was given to the Benedictine abbey of Monte Cassino, in the expectation that he would eventually become abbot.

When the troops of Frederick II occupied the abbey in 1239, Thomas was sent to the University of Naples; here he was attracted to the newly founded Dominican Order. After his reception into the Order, he was sent to Paris, so that he might be out of reach of his powerful family’s opposition; on his way there, in 1244, he was seized by an armed party north of Rome and confined in the family castle for nearly two years. On his release he began his theological studies in the Dominican priory of St. Jacques in the University of Paris. Here he came under the influence of St. Albertus Magnus, with whom he continued his studies at Cologne from 1248–51.

After his return to Paris, he lectured, as cursor biblicus, on Isaiah and Jeremiah, and then as bachelor, on the Sentences of Peter Lombard. His De Ente et Essentia (against Avicebron) dates from this period. In 1256, Thomas wrote the Contra Impugnantes Dei Cultus defending the mendicant orders against the attacks of the secular doctors, notably against William of St. Amour’s De Periculis Novissorum Temporum.

In July 1256 Thomas became a Master of Theology and for the next three years served as a Regent Master of St. Jacques. His Quaestiones Disputatae de Veritate derive from this teaching activity. Just before he left Paris, Thomas began composing the Summa contra Gentiles, a treatise apparently designed for the use of Dominican missionaries in their dealings with non-Christians.

Thomas returned to Italy in 1259 and served as lector in various Dominican houses, but his exact movements are not clear. Probably by 1261 he was in Orvieto, where he produced several works at the request of Pope Urban IV. He examined a collection of Greek patristic writings (some of them forged) which purported to support doctrinal teaching, and replied cautiously in Contra Errores Graecorum. In the Catena Aurea, a continuous gloss on the Gospels compiled from patristic sources, he included various previously unknown Greek texts which were to influence his own theology profoundly. He composed a liturgy for the feast of Corpus Christi which Urban intended to institute throughout Latin Christendom (his authorship of these texts has been disputed but is now increasingly accepted).

While at Orvieto, Thomas also wrote a literal exposition of Job. In 1265 he was sent to Rome to direct a Dominican studium at Santa Sabina. Here he began the Summa Theologiae, originally designed as a handbook for friars not bound for university study. Throughout his time in Italy he held regular disputations, including those on power, on evil, and on spiritual creatures.

In 1268 Thomas returned to Paris; he held one of the Dominican chairs of theology in the university until 1272. He was involved in controversy not only with Gerard d’Abbeville and other secular masters over the rights of the mendicants, but also with Siger of Brabant and radical Aristotelians in the Arts Faculty as well as conservative theologians opposed altogether to the use of Aristotle in theology.

During this period, which was his most productive, Thomas lectured on Matthew, John, and part at least of the Pauline corpus, and he held disputations on the soul, on the virtues, on whether the union in Christ was one of nature or of person. He again defended the mendicants in Contra Doctrinam Retrahentium a Religione, and he expounded his views on perfection, against both Franciscan and secular critics, in De Perfectione Vitae Spiritualis.

Thomas also continued work on the Summa Theologiae, completing the Second Part, and he prepared for publication literal expositions of some of the major works of Aristotle used in the schools, including Ethics, Posterior Analytics, and Metaphysics. He also finished a commentary on Dionysius the Pseudo-Areopagite’s “Divine Names.”

At Easter 1272, Thomas returned to Italy. Commissioned by his Provincial Chapter to establish a studium somewhere within the Roman Province of the Dominican Order, he chose his own priory at Naples. There he continued the Third Part of the Summa Theologiae and his expositions on other philosophical works of Aristotle and on the Platonist Liber de Causis, lectured on the Pauline Epistles, and preached to the people of Naples during Lent 1273; these sermons were cast in the form of commentaries on the Creed, the Lord’s Prayer, and the Hail Mary.

On December 6, 1273, while saying Mass, Thomas underwent some mysterious traumatic experience, which abruptly ended his teaching and writing. “Everything I have written seems like straw by comparison with what I have seen and what has been revealed to me,” he reported. In February of 1274, on his way to the Second Council of Lyons, he suffered a head injury and died on March 7, 1274 at the Cistercian abbey of Fossanuova, where he was buried.


Adapted from The Oxford dictionary of the Christian Church (3rd ed. rev., pp. 1625–1628) F.L. Cross & E.A. Livingstone, Eds. (2005). Oxford; New York: Oxford University Press, courtesy of Verbum.

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