In 1264 in the town of Orvieto, St. Thomas Aquinas composed the Lauda Sion as the Mass sequence for Pope Urban IV’s new universal solemnity of the Body and Blood of our Lord Jesus Christ, the feast of Corpus Christi. The present paper will consider this text of St. Thomas’s liturgical sequence in relation to the eucharistic theology that he teaches in the Summa Theologiae. Just as, according to the Dionysian Aquinas, the Psalms contain all the doctrines revealed in the rest of scripture but transposed into the highest literary genre of praise, so the Lauda Sion contains all the essential eucharistic doctrines of the Summa Theologiae, now set in that same laudatory genre as the Psalter. The paper is divided into ten sections, corresponding to the questions in St. Thomas’s treatment of the Holy Eucharist in the Tertia Pars. Proceeding one topic at a time, this paper will show how the Lauda Sion serves as a doxological compendium of St. Thomas Aquinas’s whole eucharistic theology.

While the story of Thomas Aquinas and Bonaventure of Bagnoregio engaging in a friendly contest, at the behest of Pope Urban IV, to compose the Mass and Office of Corpus Christi is likely a pious fiction, one can still ponder the fascinating hypothetical scenario: had such a contest taken place, who might have won? To consider that question, this paper embarks on a close reading of Bonaventure's hymns in his Office of the Passion, comparing his poetic approaches to those of Aquinas in the hymns for Corpus Christi. After an introductory historical examination into the supposed involvement of both friars in the composition of the Corpus Christi liturgy, this article proceeds in three sections. First, a look into select excerpts from Bonaventure's Office of the Passion will establish his general poetic technique. In the transitional second section, a direct comparison between Bonaventure and Aquinas on the composition of the final doxological verses of their respective hymns will place their different poetic styles into greater relief. Third, a broader reading of Aquinas's Eucharistic hymns will highlight the unique qualities of his versified praises. Finally, in light of the foregoing analyses, a prospective winner of the hypothetical contest will be suggested.

St Thomas Aquinas' antiphon from the Office of Corpus Christi, O sacrum convivium, enjoys popularity and remains part of the Liturgy of the Hours, as do other parts of the Office and Mass he composed for the feast. It offers a survey of Eucharistic theology, evoking past (‘the memory of the Passion’) present (‘the soul filled with grace’) and future (‘pledge of future glory’). It points, too to the Eucharistic flavour of authentic Christian spirituality, always remembering the self-giving of the Saviour ‘for us’, becoming what it has received in the Eucharist, and straining forward towards a goal whose foretaste is ever on our lips. On other occasions Aquinas points to these three dimensions of any sacrament, finding its source in the passion of Christ, its content in the effect achieved in the soul and its aim in the glory of communion with God. a goal whose foretaste is ever on our lips. On other occasions Aquinas points to these three dimensions of any sacrament, finding its source in the passion of Christ, its content in the effect achieved in the soul and its aim in the glory of communion with God.