During the Catholic Counter-Reformation, the Council of Trent commissioned the Roman Catechism (or Catechism of the Council of Trent, published 1566) to expound doctrine and to improve the theological understanding of the clergy. It differs from other summaries of Christian doctrine for the instruction of the people in two points: it is primarily intended for priests having care of souls (ad parochos), and it enjoyed an authority within the Catholic Church equalled by no other catechism until the Catechism of the Catholic Church (1992). The need of a popular authoritative manual arose from a lack of systematic knowledge among pre-Reformation clergy and the concomitant neglect of religious instruction among the faithful.
During the Protestant Reformation, the popular tracts and catechisms of Martin Luther, John Calvin and other Reformers were sold in areas controlled by Protestant monarchs, who determined the faith in their region (see: Cuius regio, eius religio). Catholic Catechisms, published by individuals existed as well. The Jesuit Petrus Canisius had published such a Catechism in 1555 in both German and Latin language. The Council of Trent commissioned the first Church-wide Roman Catholic catechism. This catechism was directed to clergy. It included large parts of the Canisius catechisms including his addition to the Hail Mary: Holy Mary, Mother of God, pray for us sinners.
The Fathers of the council said they wished "to apply a salutary remedy to this great and pernicious evil, and thinking that the definition of the principal Catholic doctrines was not enough for the purpose, resolved also to publish a formulary and method for teaching the rudiments of the faith, to be used by all legitimate pastors and teachers" (Cat. praef., vii). This resolution was taken in the eighteenth session (26 February 1562) on the suggestion of Charles Borromeo; who was then giving full scope to his zeal for the reformation of the clergy. Pius IV entrusted the composition of the Catechism to four distinguished theologians:
- Leonardo Marini, Archbishop of Lanciano;
- Muzio Calini, Archbishop of Zara;
- Egidio Foscherari, Bishop of Modena; and
- Francisco Fureiro, a Portuguese Dominican.
Three cardinals were appointed to supervise the work. Charles Borromeo superintended the redaction of the original Italian text, which was finished in 1564. Cardinal William Sirletus then gave it the final touches, and the famous Humanists, Julius Pogianus and Paulus Manutius, translated it into classical Latin. It was then published in Latin and Italian as "Catechismus ex decreto Concilii Tridentini ad parochos Pii V jussu editus, Romae, 1566" (in-folio). Translations into the vernacular of every nation were ordered by the Council (Sess. XXIV, "De Ref.", c. vii).
The Council intended the projected Catechism to be the Church's official manual of popular instruction. The seventh canon, "De Reformatione", of Sess. XXIV, runs: "That the faithful may approach the Sacraments with greater reverence and devotion, the Holy Synod charges all the bishops about to administer them to explain their operation and use in a way adapted to the understanding of the people; to see, moreover, that their parish priests observe the same rule piously and prudently, making use for their explanations, where necessary and convenient, of the vernacular tongue; and conforming to the form to be prescribed by the Holy Synod in its instructions (catechesis) for the several Sacraments: the bishops shall have these instructions carefully translated into the vulgar tongue and explained by all parish priests to their flocks . . .". In the mind of the Church the Catechism, though primarily written for the parish priests, was also intended to give a fixed and stable scheme of instruction to the faithful, especially with regard to the means of grace, so much neglected at the time. To attain this object the work closely follows the dogmatic definitions of the council. It is divided in four parts:
- I. The Apostles' Creed;
- II. The Sacraments;
- III. The Decalogue;
- IV. Prayer, especially The Lord's Prayer.
It deals with the papal primacy and with Limbo, points which were not discussed or defined at Trent; on the other hand, it is silent on the doctrine of Indulgences, which is set forth in the "Decretum de indulgentiis", Sess. XXV. The bishops urged in every way the use of the new Catechism; they enjoined its frequent reading, so that all its contents would be committed to memory; they exhorted the priests to discuss parts of it at their meetings, and insisted upon its being used for instructing the people.
To some editions of the Roman Catechism was prefixed a "Praxis Catechismi", i.e. a division of its contents into sermons for every Sunday of the year adapted to the Gospel of the day.
The Catechism has not of course the authority of conciliary definitions or other primary symbols of faith; for, although decreed by the Council, it was only published a year after the Fathers had dispersed, and it consequently lacks a formal conciliary approbation. During the heated controversies de auxiliis gratiae between the Thomists and Molinists, the Jesuits refused to accept the authority of the Catechism as decisive. Yet it possesses high authority as an exposition of Catholic doctrine. It was composed by order of a council, issued and approved by the pope; its use has been prescribed by numerous synods throughout the whole Church; Leo XIII, in a letter to the French bishops (8 Sept., 1899), recommended the study of the Roman Catechism to all seminarians, and pontiff, Pius X, signified his desire that preachers should expound it to the faithful.
Early editions 
The earliest editions of the Roman Catechism are: "Romae apud Paulum Manutium", 1566; "Venetiis, apud Dominicum de Farrisö, 1567; "Coloniae", 1567 (by Henricus Aquensis); "Parisuis, in aedibus. Jac. Kerver", 1568; "Venetiis, apud Aldum", 1575; Ingolstadt, 1577 (Sartorius). In 1596 appeared at Antwerp "Cat. Romanus ... quaestionibus distinctus, brevibusque exhortatiunculis studio Andreae Fabricii, Leodiensis". (This editor, A. Le Fevre, died in 1581. He probably made this division of the Roman Catechism into questions and answers in 1570).
George Eder, in 1569, arranged the Catechism for the use of schools. He distributed the main doctrines into sections and subsections, and added perspicuous tables of contents. This work bears the title: "Methodus Catechismi Catholici".
The first known English translation was commissioned by James II, the last Catholic King of England, and is entitled “The Catechism for the Curats, compos’d by the Decree of the Council of Trent, And Published by Command of Pope Pius the Fifth.” Translated by John Bromley, Printed by Henry Hills, Printer to the King’s Most Excellent Majesty for His Houshold and Chappel, for him and Matthew Turner, London, M. DC. LXXXVII. (1687) 
The next English translation is by Jeremy Donovan, a professor at Maynooth, published by Richard Coyne, Capel Street, Dublin, and by Keating & Brown, London, and printed for the translator by W. Folds & Son, Great Shand Street, 1829. An American edition appeared in the same year. Donovan's translation was reprinted at Rome by the Propaganda Press, in two volumes (1839); it is dedicated to Cardinal Fransoni, and signed: "Jeremias Donovan, sacerdos hibernus, cubicularius Gregorii XVI, P. M." There is another English translation by R.A. Buckley (London, 1852), which is more elegant than Donovan's and claims to be more correct but is spoiled by the doctrinal notes of the Anglican translator. The first German translation, by Paul Hoffaeus, is dated Dillingen, 1568. The translation into the Celtic Breton language of the "catechisme de Canisius," as it was known in France, was accomplished in 1568 by Gilles de Keranpuil, canon of the college of Carhaix and recteur of Motreff; he introduced his work in his transmittal letter to his superior as the effort '[de tradui en nostre langue brette [Breton]." This effort at translation set a precedent for the later successful efforts of Pere Julien Maunoir, S.J. of Plevin, Brittany.
- Gerhard J. Bellinger: Bibliographie des Catechismus Romanus: Ex Decreto Concilii Tridentini ad Parochos 1566-1978. Baden-Baden 1983 - ISBN 3-87320-087-2
- Petrus Canisius, ( ed Friedrich Streicher), S P C CATECHISMI Latini et Germanici, I, Roma, Munich, 1933
- Petrus Canisius, Marienlexikon, Eos, St. Ottilien 1988
- Dodd iii, 459; Wing C1742; Gillow i, 310 -- Gillow also lists an earlier English translation of the Catechism under Fenn in 1562, but it lacks any publication information. His Bromley biography includes a quote from J. Waterworth’s book, The Decrees and Cannons of the Council of Trent, 1848, Dolman, London, and found in a footnote from the preface:
An anonymous translation appeared in 1687; but it is so unfaithful and even ludicrously absurd, that it might be regarded rather as a burlesque, than a translation, of the decrees.
Gillow lists the Catechism as Bromley’s sole work, so it is puzzling that Gillow would even mention this. The quote from Waterworth is referring to another book printed anonymously in 1687, which is a translation of the Decrees and Cannons of the Council of Trent. This book is not attributed to Bromley by Dodd, or by Gillow himself. The DNB does make this attribution, but only on conjecture saying:
…and probably he was also the translator of “The Canons and Decrees of the Council of Trent.
The DNB lists as references several sources, but fails to list one that substantiates this supposition. The only references given are primarily concerned with Bromley’s reputed teaching of the child Alexander Pope, and another references to a William Bromley. This confusion in Gillow, and statement by Waterworth is all the more unjustified, since the biographical notice in Dodd states that Bromley is a good scholar in the classics, suggesting the translation of the Catechism was not one that would warrant such a derogatory comment. In any event I have compared the translations in very many places, particularly in areas of very important matter such as the treatment of the Eucharist. I have found that Bromley’s translation (other than his older English style) is in perfect agreement with the best modern editions available. The Bromley edition is heavily annotated with Scriptural and Early Church Father references in the margins.
- The Catechism of Trent
- The Catechism of Trent (1829 translation) - Internet Archive
- Catechismus ex decreto Concilii tridentini ad parochos (1856) (Latin text) - Google books