As a consequence of the encyclical Aeterni Patris (1879), a commission was formed in 1880 for preparing new editions of the writings of St. Thomas Aquinas and was named after Pope Leo XIII. A committee of three cardinals headed by the Dominican Thomas Zigliara inaugurated the enterprise. The pope had desired texts corrected from the best manuscripts that could be rapidly published for use in the Thomistic revival. However, the commission soon realized that a study of all extant manuscripts alone could produce definitive editions, so that in 1893 it became a project solely of the Dominican Order. The Leonine editions are highly regarded, their editorial method set new standards, and they have significantly contributed to the development of medieval textual criticism.
In the first period (to 1930) the Summa theologiae and the Summa contra Gentiles were completed, together with Aristotelian commentaries on logic and natural philosophy. When the commission had practically become defunct, the Order launched a revival in 1948, and besides the original group sections were founded in Spain, Canada, and the United States. In this second period sixteen editions were brought to completion, some winning the greatest acclaim. Now at the opening of a new century almost all the experienced researchers have ceased their labor, so that another beginning commences with new recruits. Although the membership has always chiefly been composed by Dominicans, as Leo XIII insisted, lay scholars have been associated with the project and have been editors of some texts. At present two non-Dominicans are full members. The American Section, located at the Dominican House of Studies, Washington, D.C., has as its projects the Sententia libri Metaphysicae ; the Scriptum, the Third Book of the Sentences of Peter Lombard; and the Quaestio disputata De spiritualibus creaturis (now published). The St. Thomas Aquinas Foundation contributes financial assistance.
The state of the edition at present is as follows. Tomes that have been published:
t. 1 v.1 Expositio libri Perhermenias, 1882, new ed. 1989;
t. 1 v.2 Expositio libri Posteriorum Analyticorum, 1882, new ed. 1989;
t. 2 In Aristotelis libros Physicorum, 1884;
t. 3 In Aristotelis libros De caelo … Meteorologicorum, 1886;
t. 4–12 Summa theologiae, 1888–1906;
t. 13–15 Summa contra Gentiles, 1918–1930;
t. 16 Indices in tomos 4–15, 1948;
t. 22 QD De veritate, 1970–1976;
t. 23 QD De malo, 1982;
t. 24 v.1 QD De anima, 1996;
t. 24 v.2 QD De spiritualibus creaturis, 2000;
t. 25 Quaestiones De quolibet, 1996;
t. 26 Expositio super Iob, 1965;
t. 28 Expositio super Isaiam, 1974;
t. 40–43 Opuscula I–IV, 1967–1979;
t. 45 v.1 Sententia Iibri De anima, 1984;
t. 45 v.2 Sententia libri De sensu, 1985;
t. 47 Sententia libri Ethicorum, 1969;
t. 48 Sententia libri Politicorum, 1971;
t. 50 Super libros Boetii De Trinitate, De hedomadibus, 1992.
In various stages of preparation:
t. 17–20 Scriptum Super IV Sententiarum
t. 21 QD De potentia
t. 24, 3 QD De virtutibus, etc.
t. 30 Super Matthaeum
t. 31 Super loannem
t. 32–35 Super Epistolas Pauli Apostoli
t. 44 Opuscula V
t. 46 Sententia libri Metaphysicae
t. 49 Super liberum De causis, Super librum Dionysii divinis nominibus.
Tomes not begun:
t. 27 Super Psalmos
t. 29 Super Ieremiam et Threnos
t. 36–39 Glossa continua super Evangelia (Catena aurea)
Bibliography: g. m. grech, "The Leonine Edition of the Works of St. Thomas Aquinas," in From an Abundant Spring, The Walter Farrell Memorial Volume of The Thomist (New York 1952) 218–258. l. j. bataillon, "L'Édition léonine des oeuvres de saint Thomas et les études médiévales," Atti dell'VIII Congresso Tomistico Internazionale 1 (1981) 425–464. p. m. de contenson, "Documents sur les origines et les premières années de la commission léonine," in St. Thomas Aquinas, 1274–1974; Commemorative Studies (Toronto 1974) 2:331–388.
[j. f. hinnebusch]