catechism (kătˈəkĭzəm) [key] [Gr., = oral instruction], originally oral instruction in religion, later written instruction. Catechisms are usually written in the form of questions and answers. Almost as old as Christianity, they were used especially for the instruction of converts and children. Catechisms were popular in the later Middle Ages and assumed even greater significance in the Reformation through Martin Luther's emphasis on the religious education of children. His Small Catechism (1529) is still the standard book of the Lutheran church. The greatest Calvinist catechism was the Heidelberg Catechism (1563). It was revised at Dort (1619) and was used in Dutch and German Reformed churches; other catechisms are the Longer and Shorter Catechisms of 1647 and 1648, drawn up to supplement the Westminster Confession; they are used in Presbyterian churches. The catechism for the Anglican Communion is included in the Book of Common Prayer.
A catechism long in use in the Roman Catholic church was that prepared by the Jesuit Peter Canisius, which appeared in 1555. The catechism of the Council of Trent, a document of high authority issued in 1566, was essentially a manual of instruction for use by the clergy in combating the Protestant Reformation; nonetheless it remained influential for over four centuries. The best-known Catholic catechism in England for many years was the Penny Catechism, adopted by the bishops of England and Wales; that in the United States was the Baltimore Catechism. The first new universal catechism of the Catholic church since that of the Council of Trent was released in French in 1992 and in English in 1994. The book forgoes the traditional question-and-answer format, instead providing a compendium of Roman Catholic teaching and belief. A summary of the catechism that employs a question-and-answer formate was released in 2005.