Congregational singing is the practice of the congregation participating in the music of a church, either in the form of hymns or a metrical Psalms or a free form Psalm or in the form of the office of the liturgy (for example Gregorian chants).^[1] It is contrasted with music being sung exclusively by a choir or cantor(s). Congregational singing was largely the invention of the Protestant Reformation. Before then, singing in churches, especially in larger urban churches, was largely left to professionals.^[2] The reformers in Strasbourg, in particular, reduced the church service largely to a sermon bookended by congregational singing and prayers.^[2]