Recovering the Text, Serving the Truth
The Leonine Commission is a group of researchers charged with preparing the critical edition of the complete works of St. Thomas Aquinas. Its task is not simply to reproduce texts, but to establish them with scholarly precision, drawing on manuscripts, historical witnesses and the methods of critical philology.
This work serves theologians, philosophers, historians, students and all who turn to St. Thomas as a teacher of sacred doctrine. By clarifying the textual tradition of Aquinas, the Commission helps ensure that his thought may be studied and received with fidelity.
“Among the Scholastic Doctors, the chief and master of all towers Thomas Aquinas, who, as Cajetan observes, because 'he most venerated the ancient doctors of the Church, in a certain way seems to have inherited the intellect of all.' The doctrines of those illustrious men, like the scattered members of a body, Thomas collected together and cemented, distributed in wonderful order, and so increased with important additions that he is rightly and deservedly esteemed the special bulwark and glory of the Catholic faith.”
— Pope Leo XIII, Aeterni Patris
Before the Leonine edition of De veritate, common editions contained at least 10,000 variants that were more or less faulty in relation to the original. The Leonine Commission leads scholars past corrupted or uncertain texts, to the thought of Saint Thomas himself.
The Leonine Commission takes its name from Pope Leo XIII, who founded the project in 1879 as part of the renewed attention to St. Thomas Aquinas in the life of the Church. Soon entrusted to the Dominicans, the critical edition produced became known as the Leonine Edition.
During its first period, from 1879 to 1949, the Leonine Commission published sixteen volumes. After a period of reorganization from 1949 to 1952, the Commission continued its research and editorial work according to stricter critical methods and with more systematic attention to the manuscript tradition.
Principally based in Paris since 2003, the Leonine Commission continues this service today, working at the intersection of theology, philosophy, history, Latin philology and manuscript studies.
Today, the Leonine Commission is entirely supported by the Order of Preachers. This means providing for its annual operating expenses and, above all, supporting its researchers.
The works of St. Thomas Aquinas remain one of the great reference points in the history of Western thought. They continue to shape theology, philosophy, ethics, law and the broader intellectual tradition of the Church. At the same time, interest in Aquinas reaches far beyond Catholic circles. Universities, research centers and scholarly institutions around the world recognize the Leonine Edition as an essential resource for the study of medieval thought and the history of ideas.
This is one reason the work of the Leonine Commission matters so deeply. Its editions do not serve only a small circle of specialists. By establishing reliable texts, the Commission makes it possible for scholars, translators, teachers and students to encounter Aquinas more directly and accurately.
The first readers of these large-format Latin volumes are often university researchers and experts. But their impact is much wider. As the Leonine texts are translated into modern languages, they open the writings of St. Thomas to new generations of readers. In this way, the Commission helps people encounter Aquinas not only through later commentators or disciples, but through his own words.
“At the heart of the Order and in cooperation with the academic institutions of the highest level and the most qualified researchers, the Leonine Commission works on the critical edition of the writings of Saint Thomas. It thus develops the understanding of the cultural and historical context of his teaching.” (ACG Biên Hòa 2019, 361)
