Also known as the Catechism of the Council of Trent, or the Catechism for Parish Priests, or the Catechism of Pius V. The preparation of such a work was ordered by the Council of Trent (1545-1563) and brought out in the year 1566, under Saint Pius V. The division of the subject-matter follows the four formulas: the Creed, the Sacraments, the Decalogue, the Lord's Prayer. Saint Charles Borromeo deserves the largest share of credit for the composition of the work. The Catechism is not a school-book, but a manual for the catechist and teacher. It brought about a much-needed uniformity of Christian doctrine and dealt a staggering blow to Protestant claims.