school for religious education, usually for children and young people and usually a part of a church or parish. The movement has been important primarily in Protestantism (Protestant Heritage). It has been the foremost vehicle for teaching the principles of the Christian religion and the Bible.

Although religious education of various types had been known earlier within Christianity, the beginning of the modern Sunday school can be traced to the work of Robert Raikes (Raikes, Robert) (1736–1811), a newspaper publisher in Gloucester, Eng., who was interested in prison reform. He decided that young children, many of whom were employed in factories every day except Sunday, could be deterred from a life of crime if they were given basic and religious education on Sundays. The first school was opened in 1780 with the cooperation of the Anglican parish minister, although lay people were in charge. Classes were held in the teachers' homes. After three years, Raikes's writing about the Sunday schools in Gloucester in his newspaper aroused interest, and the system was copied throughout the British Isles (United Kingdom). Some church officials opposed the schools because they thought that teaching interfered with the proper observance of Sunday, and others did not believe in educating the poor because it might lead to revolution. Eventually, however, the Sunday schools became closely associated with the churches. When Raikes died, 31 years after the first school was opened, it was reported that about 500,000 children in the British Isles were attending Sunday schools.

The movement spread to the European continent and to North America. In Europe, however, because religious instruction was usually given in the regular schools, the Sunday schools were not so important as they were in the United States, where the separation of church and state prohibited religious instruction in the public schools.

In the United States each denomination generally established its own Christian education policy, although interdenominational cooperation was frequently an important factor. The Philadelphia Sunday School Union, the first interdenominational Sunday school association in the United States, was organized in 1791. The International Council of Religious Education, which was organized in 1922, became part of the National Council of Churches in 1950.

Various systems of teaching have been used in the Sunday schools. The Bible and the denomination's catechism were usually the materials used for instruction until special church-school materials were developed and curricula were constructed to reflect the doctrinal (and social) positions of the various denominations. Teachers are sometimes lay volunteers and are sometimes specially trained. The teaching schedule follows the school year, with vacation bible (or church) schools held for one or two weeks during the summer.

The Eastern Orthodox (Eastern Orthodoxy) churches also conduct church schools, but the movement has never been as important as in Protestantism. Roman Catholics (Roman Catholicism) generally have not adopted the Sunday school system but, instead, have provided religious instruction with general education within their own church-affiliated schools.