Aquinas and Corpus Christi: Theologian, Poet, and Mystic
St. Thomas Aquinas didn't just write about the Eucharist — he was commissioned to shape how the whole Church would worship the Body of Christ.
The Commission
Pope Urban IV asked St. Thomas Aquinas — who was accompanying the pope at the time and was in Orvieto — to compose the texts of the Liturgical Office for the great feast of Corpus Christi. These texts are masterpieces still in use in the Church today, in which theology and poetry are fused — expressing praise and gratitude to the Most Holy Sacrament while the mind, penetrating the mystery with wonder, recognizes in the Eucharist the Living and Real Presence of Jesus.
The Hymns
Sometime between 1259 and 1264, Thomas composed the words to the Pange Lingua and the Verbum Supernum — the last two verses of each being the Tantum Ergo and the O Salutaris respectively.
He also wrote the antiphon O Sacrum Convivium for the Office of Corpus Christi, which serves as a wonderful summary of Eucharistic theology. It proclaims that in the Eucharist, Christ is received, the memory of His Passion is recalled, the mind is filled with grace, and a pledge of future glory is given.
Each of these hymns provides great doctrinal statements of the truths of the Incarnation, the Paschal Mystery, and the Eucharist, while expressing devotion to Jesus Christ as Lord and Redeemer.
The Theology Behind the Poetry
Aquinas was not merely a poet — his hymns are compressed systematic theology set to music:
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Real Presence: To Aquinas, the Eucharist is the body and blood of Christ under the appearances of bread and wine — a central tenet of Eucharistic theology.
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Transubstantiation: He employed Aristotelian concepts to explain how the substance of bread and wine becomes the body and blood of Christ — a process known as transubstantiation.
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Old Testament Typology: Aquinas grounded the Eucharist in biblical foundations, drawing from Old Testament prefigurations, seeing figures such as the manna from heaven and the Passover as foreshadowing the Eucharist.
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Memorial of the Passion: After all their subtle distinctions and discussions, Aquinas's writings on the Eucharist are finally led back to the heart of Catholic Eucharistic theology — "the memorial of Christ's Passion" — and in reviewing them, one finds the most enlightening and complete synthesis of the Catholic faith concerning the mystery of the Eucharist.
A Personal Devotion
Aquinas didn't hold the Eucharist at arm's length as a mere theological puzzle. His biographer William of Tocco records that before receiving Viaticum near death, Thomas prayed: "I receive you, price of my soul's redemption… for love of you I have studied, watched and toiled."
St. John Paul II, in Ecclesia de Eucharistia, called Thomas "an eminent theologian and an impassioned poet of Christ in the Eucharist."
Aquinas shows that the deepest theology doesn't end in cold abstraction — it ends on its knees in adoration.
What aspect of Aquinas's Eucharistic theology strikes you most — the philosophical precision of transubstantiation, the biblical typology, or the devotional beauty of the hymns — and why do you think he felt compelled to express the same truth in both forms?
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