The Mass, which is the central service of the Catholic church, is traditionally divided into recognisable sections. Many of these have repeatedly been set to music.
The earliest settings of the words of the Mass were in plainsong. Those parts of the service which vary from season to season and day to day, called the Proper of the Mass, usually continued to be set in that way. However, with the development of musical forms and instruments, many of the invariable sections of the Mass, known as the Ordinary, came to be set for solo voices and choruses. These follow the recognisable fashions of the music of their day.
The sections of the Ordinary most usually set for chorus and soloists are: Kyrie, ( ΓÇ£Lord, have mercy ...ΓÇ¥) Gloria ( ΓÇ£Glory to God in the highest...ΓÇ¥ ), Credo, ( ΓÇ£I believe ...ΓÇ¥ ) Sanctus - often with the Benedictus separated from it - ( ΓÇ£Holy, holy, holy .... Blessed....ΓÇ¥ ), Agnus Dei, ( ΓÇ£Lamb of God ....ΓÇ¥ ).
A high point in religious composition was reached in Europe at the end of the sixteenth century. The next two centuries saw a move away from an unaccompanied choral contrapuntal style to less devotional, more sophisticated, treatments. These reveal an increased understanding of the principles of orchestral accompaniment, as well as the development of solo singing.
As time passed, the five sections of the Ordinary were frequently used by composers as the basis for oratorio-style works. These were often intended for the concert hall, rather than the church. J.S. Bach's Mass in B Minor and Beethoven's Mass in D, are examples of such works. In them, subdivisions of the five sections provide opportunities for extended choral and solo passages.
High Mass is sung throughout, usually by celebrants and choir, either in the traditional plainsong, or with the five sections of the Ordinary set by a composer.
Low Mass is traditionally sung only by the priest and an altar-boy or clerk. Nowadays many of its words are usually spoken. Song is often reduced to optional hymns which function as decoration rather than integral parts of the service.
A Folk Mass was originally a term for a Low Mass during which hymns were sung by the congregation. It has come to mean a Mass in which the congregation joins in singing extremely simple words and settings, often with guitar and percussive accompaniment.
