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Summary Article: Thomas Aquinas ca. 1224-1274
from Religions of the World: A Comprehensive Encyclopedia of Beliefs and Practices

Thomas Aquinas was a member of the Dominican Order who emerged in the 13th century as a prominent theologian best known for his use of Aristotelian philosophy as a framework for doing Christian theology and the thoroughness of his theological inquiry. He lived and taught at Paris, Naples, and Rome and wrote the Summa Theologiae, which has come to be seen as the foremost theological work of the Middle Ages. He would later be named a Doctor of the Church, a title bestowed on a very few theological writers who have been designated a saint and who in addition have written theological works from which the whole church has derived great advantage. Doctors of the Church are seen as people who have integrated outstanding intellectual accomplishments with noteworthy sanctity.

Thomas was born around 1224 as the youngest son of Landulfo d’Aquino, who sent Thomas to live among the monks at the prominent Benedictine abbey of Monte Casino with the expectation that he would rise to the position of abbot. He studied theology and philosophy at the University of Naples, recently established by his uncle Frederick II, the king of Sicily (r. 1296-1337). Thomas rejected his parents’ plans and at the age of 19 he left the Benedictines for the recently founded Dominican Order. While taking the traditional monastic vows of poverty, chastity, and obedience, the friars of the Dominican Order rejected the more internal focus of the Benedictines and offered a more outward focus on community service. It was organized as a preaching order and the friars were trained in vernacular languages (rather than exclusively emphasizing Latin). Rather than earning their living on the monastery’s property, usually in agricultural pursuits, Dominican friars survived from the gifts of those who supported their work.

Thomas’s family was horrified by his decision, and they kidnapped him and attempted to lure him back to his father’s plan. He resisted the enticements and would later write against those who attempted to force young men to leave the new orders (that would also include the Franciscans and Augustinians). He ultimately escaped his kidnappers, and his superiors sent him to study theology at the Dominican priory in Paris. In 1248, he moved on to Cologne, where for a brief period he became the student of his fellow Dominican Albertus Magnus (1193-1280).

Thomas’s education occurred just as the lost works of Aristotle were being introduced into the educational curriculum of Western institutions of higher learning following their rediscovery in the Middle East by the Crusaders. Prior to this time, almost all theology in the West was based on Platonic philosophy.

Upon his return to Paris, he completed his bachelor’s degree in scripture and lectured on the Bible and the Sentences, written by Peter Lombard (ca.1105-ca.1164), the primary theological textbook of the era. He also began to pen commentaries on the major works of Aristotle, study tools on Aristotle being as yet nonexistent. He soon received his master’s of theology degree and began work on his first major theological text, the Summa contra gentiles (Summa against the Gentiles), an apologetic treatise aimed at missionaries who were evangelizing non-Christians. Thomas was primarily concerned for his Christian brothers working among Spanish Muslims. Thomas used his knowledge of Aristotle and the several prominent Muslims whose works were circulating in the West (most notably Averroes and Avicenna) to attack the overreliance on reason they demonstrated. He observed that the truth that was, in fact, found in Islam was mixed with much falsehood. He also wrote in defense of the Dominicans and their lifestyle from those who attacked the Order.

In 1259 Thomas began a decade of teaching at various Dominican sites in Italy. During this time he wrote the liturgy for Corpus Christi, the Roman Catholic festival honoring the Eucharist, and compiled the Catena aurea (Golden Chain), a set of biblical commentaries by the early church fathers. He also began the work on his monumental magnum opus, the Summa Theologiae, which would consume most of his energy until 1273.

Upon his return to Paris in 1268, he continued his most active intellectual life. He argued with the more extreme Aristotelians; he wrote commentaries on the New Testament books of Matthew and John; he commented on Dionysius the Areopagite’s Divine Names; he penned works on the Christian creed, the Lord’s Prayer and the Hail Mary prayer; and he composed hymns and delivered sermons.

His life was radically altered on December 6, 1273. That day, while celebrating the Mass, he had an intense mystical vision. He would afterward observe, “Everything I have written seems like straw in comparison with what I have seen and what has been revealed to me.” He stopped his writing, and essentially left the Summa Theologiae unfinished. He died four months later, on March 7, 1274, while journeying to the Church Council that was about to convene in Lyon. He was buried at the Dominican church in Toulouse, France.

Thomas’s Thought Thomas’s great work, the Summa Theologiae, is constructed around a series of topical theological questions, beginning with the status of theology as a science (in the Aristotelian sense of that word). Parts 1-3 discuss the existence and triune nature of God, creation, how all beings move toward God as an end, and the incarnation of Christ that provides the means by which creatures move toward God (Part 3). In Part 1.2, Thomas discussed the beatific vision of God in terms of human destiny (his own intellectual career culminating in such a vision). He covered the Christian life in Part 2.2, where he expounds upon the theological virtues (faith, hope, and charity), the cardinal virtues (prudence, justice, courage, and temperance), and the charisms or gifts of the Spirit. He also discusses the relative merits of the contemplative versus the active patterns for living one’s life. In Part 3, Thomas covered Christology, the understanding of Jesus Christ and his salvific work and the sacramental life.

The Summa ended abruptly after Part 3. Following Thomas’s death, his secretary Reginaldo de Piperno attempted to complete it by using material from Thomas’s other writings, most notably his commentary of the Sentences of Peter Lombard, even though they had been written some 30 years previously. Most modern editions of the Summa omit the supplement.

Thomas in Context Though it would take some time to see it, Thomas essentially moved Christian theology away from its domination by Platonic (and neo-Platonic) philosophy. He did so by mastering the intellectual stream and gently moving it into the Aristotelian camp rather than attempting a harsh break with the past. He emphasized his alignment with all that had preceded him and moved forward into an emerging work that would value science, technology, and urban life.

At the same time, Thomas made a crucially important shift in Christian thinking. Plato had pointed beyond the ultimately unreal world of the manifest world observed by the senses to the superior reality of the realm of ideas. Christian Platonists tended to subordinate time, space, and the physical world to an eternal spiritual realm. Disciplines of study, which allow us to master the social and physical, are devalued relative to theology. Thomas’s theology gave an enlarged place for the empirical arts and sciences (law, medicine, natural science, architecture, and engineering), and a new level of legitimacy. Following Aristotle’s lead, Thomas provided a place for empirical observation as a proper, natural, and necessary human endeavor.

Thomas’s theology also supplied the church with a new philosophical language. Since the end of the centuries of persecution and its quick emergence as the dominant religion of the Roman Empire in the fourth century, the Christian church’s major thinkers had relied on Platonic thought forms. Plato had provided the background for the discussions at the Ecumenical councils at which the basic statements of Christian orthodoxy had been hammered out and from which the Nicene and Chalcedonian creeds promulgated. As Thomas turned to the subject of Christology, he aligned himself fully with the church councils and ancient creeds, while presenting a new emphasis on God’s action. In Christ, God entered the world not only to save humanity from sin, but to lift it up to the divine. Also, in entering the world, God reasserts the primal creative pronouncement that the created world is good—further basis for the legitimacy of the human arts and sciences.

The last section of the Summa that Thomas completed dealt with the sacraments. Catholicism is a sacramental religion, and the sacraments are given for the redemption from sin, and also, as Thomas emphasizes, as tools to assist the individual believer on his or her pilgrimage toward sanctification (holiness). In the process of writing about the sacraments, Thomas would also offer an explanation of the essential action that took place in the Eucharist when the elements of bread and wine were transformed into the Body and Blood of Christ. Drawing on the philosophical distinction between an object’s essence or substance and its particular attributes (appearance, texture, taste, color, smell) observed by the five senses, he suggested that in the Mass, the essence/substance of the bread and wine became the body and blood of Christ while the attributes remained unchanged. This change became known as transubstantiation.

Thomas Aquinas Today Thomas’s views were not immediately accepted in his own day, though he found strong support. Just five years after Thomas’s death, the general chapter of the Dominicans pronounced penalties against any of their number who would speak irreverently of Thomas or his writings, and subsequent chapter gatherings expressly required the brethren to follow his teachings. In the church’s seminaries, the Summa gradually replaced Lombard’s Sentences as the primary textbook for theology, especially after his canonization by Pope John XXII (r. 1316-1334) in 1323 ended any remaining open opposition.

Thomas’s thought took an upward trajectory at the Council of Trent, called in large part to deal with the growth of Protestantism. The Council relied heavily on Thomas in its deliberation and the Catechism of the Council of Trent (1545-1563), prepared for the use of parish priests, can be seen as essentially a summary statement of his theology. In 1567, Pope Pius V named him a Doctor of the Church, after which the Summa Theologiae came to replace Lombard’s Sentences as the chief text for teachings theology in Catholic seminaries.

By the 19th century, the use of Thomas’s writings had declined, but a revival occurred during the pontificate of Pope Pius IX (r. 1846-1878), who presided over the First Vatican Council (1870-1871). Then in one of his first actions after becoming pope, his successor, Pope Leo XIII (r. 1878-1903), called for a continuance of the revived interest in his 1879 encyclical Aeterni Patris. He recommended the study of Thomas by all Catholic theological students throughout the world, though not to the exclusion of others. Leo also led in the formation of the Leonine Commission, which produced new critical editions of many of Thomas’s works.

The centrality of Thomas’s place in the theology of the Catholic Church was challenged by the Second Vatican Council and many believed his period of dominance had ended. He has, however, shown a significant resiliency and continues to remain a key force in Catholic theological discourse.

See also:

Augustinians; Benedictines; Dominicans; Franciscans; Roman Catholic Church; Theology.

  • The Summa Theologiae is available on the Internet at and a printed version is the Blackfriar’s edition (London, 1964-1981); the complete edition of Thomas’s works is the Leonine edition (Rome, 1882-).
  • Chenu, Marie-Dominique. Toward Understanding St. Thomas. Chicago: Regnery, 1964.
  • Copleston, Frederick C. Aquinas. Harmondsworth, UK: Penguin, 1955.
  • Gilson, Etienne. The Christian Philosophy of St. Thomas. New York: Random House, 1964.
  • Pieper, Joseph. Guide to Thomas Aquinas. New York: Pantheon, 1962.
  • Selman, Francis. Aquinas 101: A Basic Introduction to the Thought of Saint Thomas Aquinas. Orleans, MA: Christian Classics, 2007.
  • Torrell, Jean-Pierre. Saint Thomas Aquinas: The Person and His Work. Washington, DC: Catholic University of America Press, 2005.
  • Weisheipl, James. Friar Thomas d’Aquino. Washington, DC: Catholic University of America Press, 1983.
  • Melton, J. Gordon
    Copyright 2010 by ABC-CLIO, LLC

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