# Compendium of Theology Thomas Aquinas's late, unfinished, single-author summary of Christian theology, organized around the three theological virtues. Written for his secretary Reginald of Piperno, the work was meant as a portable handbook of the faith for one reader, not as a public *summa*. Aquinas finished the section on faith and the opening of hope before he died in March 1274. What survives runs to roughly 250 chapters, the densest short-form statement of his theology in his own voice. ## Intro Thomas Aquinas spent most of his life writing the *Summa Theologiae*, his giant systematic theology in three parts, designed for university students. The *Compendium of Theology* is the opposite. It is a small book, written for one man, his secretary Reginald, who probably asked Thomas for something he could carry. Aquinas organized it around the three Christian virtues from First Corinthians 13: faith, hope, and charity. He finished the faith section and began the hope section before he died. The work breaks off in the middle of a sentence. What survives is gold. Without the back-and-forth of objections and replies that fills the *Summa*, Aquinas just states what he believes the Christian faith teaches, in his own voice, chapter by short chapter. You read his doctrine of God, the Trinity, creation, providence, angels, the soul, the resurrection of the body, the [Hypostatic Union](/codex/hypostatic-union/), and the redeeming work of Christ, all in a few hundred chapters that fit in a coat pocket. For someone learning the Christian faith, or wanting to know what one of the most careful theologians the Church has ever produced actually held, the *Compendium* is a one-volume answer. It is shorter than the *Summa* by an order of magnitude. It assumes you want the answers, not the debate. ## In full The *Compendium Theologiae ad fratrem Reginaldum socium suum carissimum* is Aquinas's late synthetic exposition of Catholic doctrine, structured around First Corinthians 13:13 ("now abide faith, hope, charity, these three"). The work is divided into three projected books: *De Fide*, *De Spe*, *De Caritate*. Book I, on faith, was completed and contains 246 chapters covering the doctrine of the one God (chapters 3-36), the Trinity (37-67), creation (68-99), providence (100-141), angels and creatures (142-148), human nature, soul, and the image of God (149-184), original sin (185-198), the incarnation (199-209), and the work of Christ (210-246). Book II, on hope, was begun and survives in 10 chapters covering the structure of Christian hope and the Lord's Prayer; it breaks off mid-sentence. Book III, on charity, was never started. Aquinas dictated the work probably between 1265 and 1273. He likely set it down around the time of his mystical experience on 6 December 1273 when, after celebrating Mass, he stopped writing entirely and told Reginald everything he had written seemed "like straw" compared to what he had seen. He died three months later on the road to the Council of Lyon. The Latin text is critical-edited in the Leonine edition of his complete works. ## Structure Aquinas takes the three theological virtues from 1 Corinthians 13 as the architectural plan for the whole work. Each book is meant to answer a single question. - **Book I, on faith**: *what should a Christian believe?* The doctrines of the faith, beginning with God's existence and unity, then His triune life, then creation, providence, anthropology, and the incarnation and saving work of Christ. - **Book II, on hope**: *what should a Christian hope for?* The structure of Christian hope and an exposition of the Lord's Prayer as the school of hope. - **Book III, on charity**: *how should a Christian love?* Never written. The threefold organization mirrors the structure of the Apostles' Creed and the catechetical pattern Aquinas already uses in shorter pieces like his *Conferences on the Creed, the Pater Noster, and the Decalogue* (1273). The *Compendium* is the most theologically dense version of this catechetical structure he produced. ## What you find in Book I The Aquinas of the *Compendium* is the same Aquinas as of the *Summa*, but stripped of the dialectical scaffolding. Chapter after chapter is a clean positive statement. - **God exists** (3-7), with the cosmological arguments compressed to their essence - **God is one, simple, perfect, eternal, infinite** (8-36), the divine attributes laid out - **God is Father, Son, and Holy Spirit** (37-67), the [Trinity](/codex/trinity/) doctrine without the medieval debate-form - **God creates ex nihilo** (68-99), with chapters on creation, providence, and the angels - **The human person** (149-184), body and soul, intellect and will, the image of God - **Original sin** (185-198), the fall, its transmission, its consequences - **The incarnation** (199-209), the doctrine of two natures and one Person, with the [Hypostatic Union](/codex/hypostatic-union/) taught clean - **The work of Christ** (210-246), satisfaction, merit, the Passion, the resurrection, the ascension, the judgment The Christology section (199-246) is especially compact: forty-eight short chapters teaching what Aquinas treats at much greater length in *Summa Theologiae* III, qq. 1-59. ## What you find in Book II Only ten chapters survive. Aquinas opens by tying hope to the Lord's Prayer and begins to walk through the petitions. He gets through about half of "Our Father, who art in heaven" before the manuscript stops. The fragment is precious because it shows how Aquinas wanted to teach hope: through the prayer Christ Himself gave. The unwritten chapters on charity would presumably have used the love command and perhaps the beatitudes. ## Why it matters today Three reasons the *Compendium* is worth reading even for non-Catholic Christians and non-specialists. 1. **It is short.** Most readers will never finish the *Summa Theologiae* (1.5 million words). The *Compendium* is finishable in a focused weekend. The doctrine you get is the same. 2. **It is uncontroversial.** Aquinas's voice without the scholastic debates around it. Catholics and many Protestants can recognize the substance as common Christian inheritance from the first millennium. 3. **It is portable.** As a working reference on what one of the major theologians of the Church actually held, the book functions today the way Reginald carried it: as a one-volume Christian theology you can keep close. For [Christology](/codex/christology/) in particular, the *Compendium* chapters 199-246 are an unusually compressed treatment. The doctrine is the same as the *Summa* III, but in a form a working pastor or apologist can absorb in a single sitting. ## Editions - **Leonine edition** (the critical Latin text), *S. Thomae Aquinatis Opera Omnia*, vol. 42, ed. H. F. Dondaine, 1979 - **English: Cyril Vollert, S.J.**, *Compendium of Theology* (St. Louis: B. Herder, 1947; reprinted Sophia Institute Press, 2009). The standard English version for most of the twentieth century. - **English: Richard J. Regan**, *Compendium of Theology* (Oxford University Press, 2009). A newer translation with introduction and notes. ## See also - [Christology](/codex/christology/), the doctrinal frame Book I converges on - [Hypostatic Union](/codex/hypostatic-union/), the Christological doctrine Aquinas teaches in chapters 199-242 - [Communicatio Idiomatum](/codex/communicatio-idiomatum/), the rule of predication Aquinas employs throughout the Christological chapters - [Trinity](/codex/trinity/), chapters 37-67 of the *Compendium* - [Christs Deity](/codex/christs-deity/), the divine side of the incarnate Son in Aquinas - [Thomas Aquinas](/codex/thomas-aquinas/), the author hub - [Catholic Church](/codex/catholic-church/), the ecclesial tradition the work was written within - [Aquinas Five Ways](/codex/aquinas-five-ways/), the longer-form version of the existence arguments compressed in chapters 3-7 ## Common questions this page answers **Q: What is the Compendium of Theology?** A short systematic theology by Thomas Aquinas, written for his secretary Reginald of Piperno around 1265-1273. Organized into three books on faith, hope, and charity, taken from 1 Corinthians 13. Aquinas finished the faith section and began the hope section before he died in March 1274. The charity section was never written. **Q: Why is the Compendium unfinished?** Aquinas had a mystical experience on 6 December 1273 after celebrating Mass and stopped writing entirely, telling Reginald that everything he had written seemed "like straw" compared to what he had seen. He died three months later on the road to the Council of Lyon. The work breaks off mid-sentence in the section on the Lord's Prayer. **Q: How is the Compendium different from the Summa Theologiae?** The *Summa* is a teaching textbook for university students, written in the question-and-objection-and-reply format of medieval scholastic debate. The *Compendium* is a portable handbook for one reader, in straight positive prose, much shorter (roughly one tenth the length). Both teach the same doctrine; the *Compendium* just states it without the scholastic apparatus. **Q: What is in Book I of the Compendium?** Book I covers the contents of Christian faith in 246 chapters: God's existence, unity, and attributes; the Trinity; creation, providence, and angels; the human soul, intellect, and will; original sin; the incarnation; and the saving work of Christ from the cross to the final judgment. The Christology section (chapters 199-246) is a compressed forty-eight-chapter exposition of the doctrine of the [Hypostatic Union](/codex/hypostatic-union/). **Q: Where can I get an English translation?** Two standard translations are available. Cyril Vollert's 1947 version (B. Herder, reprinted by Sophia Institute Press, 2009) was the standard English text for decades. Richard Regan's 2009 translation from Oxford University Press includes introduction and notes and is the current scholarly reference.