Summa contra Gentiles
The Summa contra Gentiles (also known as "", "Book on the truth of the Catholic faith against the errors of the unbelievers") is one of the best-known treatises by St Thomas Aquinas, written as four books between 1259 and 1265. It was probably written to aid missionaries in explaining the Christian religion to and defending it against dissenting points of doctrine in Islam and Judaism. To this end, Aquinas could rely on a substantial body of shared doctrine, especially tenets of monotheism, in the case of Judaism the shared acceptance of the Old Testament as scripture and  in the case of Islam the (at the time) shared tradition of Aristotelian philosophy. Whereas the "Summa Theologiæ" was written to explain the Christian faith to theology students, the "Summa contra Gentiles" is more apologetic in tone, as it was written to explain and defend the Christian doctrine against unbelievers, with arguments adapted to fit the intended circumstances of its use, each article refuting a certain heretical belief or proposition. Instead of a mere elucidation of the length and breadth of Christian doctrine, Aquinas explains specific core articles of Christian belief. Title. The conventional title "Summa contra Gentiles", found in  some of the earliest manuscripts, is sometimes given in the variant "Summa contra Gentes". The title is taken from chapter I.2, where Thomas states his intention as the work's author: I have set myself the task of making known, as far as my limited powers will allow, the truth that the Catholic faith professes, and of setting aside the errors that are opposed to it. To use the words of Hilary: 'I am aware that I owe this to God as the chief duty of my life, that my every word and sense may speak of Him' ("De Trinitate  I, 37). A longer title is also given as Tractatus de fide catholica, contra Gentiles" (or: "contra errores infidelium"), meaning "Tractate on the universal faith, against the pagans" (or, against the errors of the unbelievers). This is often shortened to "De fide Catolica". Date and composition. The work was written over a period of several years, between 1259 and 1265. In the spring of 1256 Thomas was appointed regent master in theology at Paris and one of his first works upon assuming this office was "Contra impugnantes Dei cultum et religionem", defending the mendicant orders, which had come under attack  by William of Saint-Amour. During his tenure from 1256 to 1259, Thomas wrote numerous works, and he was working on "Summa contra Gentiles" by the time he left Paris. From Aquinas's autograph, Torrell (1996) identified the first 53 chapters of Book I as having been written in Paris based on studies of the parchment and the ink used. According to a tradition that can be traced to shortly after Thomas's death, the "Summa contra Gentiles" was written in response to a request, made in 1259, for a book that would help the Dominican missionaries in Spain to  convert the Muslims and Jews there. The request was made by Raymond of Peñafort, a Dominican friar and advisor to James I of Aragon. Raymond had been active in the Christian defense against the Moors (Muslims) and Jews in the kingdom of Aragon since the 1240s. To this end, Raymond instituted the teaching of Arabic and Hebrew in several houses of the friars, and he also founded priories in Murcia (then still under Muslim rule) and in Tunis. Additionally he went to help establish the Church in the recently conquered island of Mallorca. Raymond's request to Thomas was transmitted  by fellow Dominican Ramón Martí, one of eight friars appointed to make a study of oriental languages with the purpose of carrying on a mission to Jews and Moors. The historicity of this account has been questioned in modern scholarship. Arguments adduced include the lack of an explicit dedication to Raymond, the evidence that substantial portions of book 1 were complete by mid-1259 (suggesting that Thomas started work on the book as early as 1257), and the suggestion that the work makes no effort to address tenets of Islam specifically. Later in 1259, Thomas left Paris and returned to Naples , where he was appointed as general preacher by the provincial chapter of 29 September 1260. In September 1261 he was called to Orvieto as conventual lector responsible for the pastoral formation of the friars unable to attend a "studium generale". It was in Orvieto that Thomas completed "Summa contra Gentiles", which was followed by the "Catena aurea" and minor works produced for Pope Urban IV such as the liturgy for the newly created feast of Corpus Christi and the "Contra errores graecorum". Parts of the text have survived in Aquinas's autograph, kept in the Vatican Library as Lat. 9850 . The manuscript includes fragments of books one and two, and large portions of book three. Contents. The "Summa contra Gentiles" consists of four books. The structure of St. Thomas's work is designed to proceed from general philosophical arguments for monotheism, to which Muslims and Jews are likely to consent even within their own respective religious traditions, before progressing to the discussion of specifically Christian doctrine. Books I–III cover truths that naturally are accessible to the human intellect while Book IV covers revealed truths for which natural reason is inadequate. Editions and translations. Giuseppe Ciante (d. 1670), a leading  Hebrew expert of his day and professor of theology and philosophy at the College of Saint Thomas in Rome was appointed in 1640 by Pope Urban VIII to the mission of preaching to the Jews of Rome ("Predicatore degli Ebrei") in order to promote their conversion. In the mid-1650s Ciantes wrote a "monumental bilingual edition of the first three Parts of Thomas Aquinas’ "Summa contra Gentiles", which includes the original Latin text and a Hebrew translation prepared by Ciantes, assisted by Jewish converts, the "Summa divi Thomae Aquinatis ordinis praedicatorum Contra Gentiles quam Hebraicè eloquitur…". Until the present this remains  the only significant translation of a major Latin scholastic work in modern Hebrew." The first modern edition of the work is the one by Ucceli (1878) re-published in 1918 as part of the "Editio Leonina". Appendices to the first three books, based on the authograph, were edited as vols. 13 (1918, 3–61) and 14 (1926, 3–49) of the Leonine edition. The Leonine text was re-edited, with corrections, by P. Marc, C. Pera and P. Carmello and published with Marietti, Torino-Rome, in 1961. Modern translations have been published in: English (1924, 1957), German (1937, 2001), Spanish (1968) and  French (1993, 1999).