Heidelberg Catechism

The Heidelberg Catechism, one of the Three Forms of Unity, is a Protestant confessional document taking the form of a series of questions and answers, for use in teaching Reformed Christian doctrine. It was written in 1563 in Heidelberg, present-day Germany. Its original title translates to Catechism, or Christian Instruction, according to the Usages of the Churches and Schools of the Electoral Palatinate.