Although Luther and Calvin were both reformers they differed on many things, such as predestination, the nature of Holy Communion, and the relationship of the church and state. In 1546, the controversy between Lutherans and Calvinists broke out in the Palatinate. A Catechism expressing Calvin's views was prepared by Zacharias Ursinus and Caspar Olevianus and was published in 1563 in Heidelburg, from which it took its name.

             John Calvin                            Idellette de Buré, Calvin's wife