Catechism of the Council of Trent

The Roman Catechism (or Catechism of the Council of Trent, published 1566) was commissioned during the Catholic Counter-Reformation by the Council of Trent, 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:

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