The Mass, a form of sacred musical composition, is a choral composition that sets the fixed portions of the Eucharistic liturgy (principally that of the Roman Catholic Church, the Churches of the Anglican Communion, and also the Lutheran Church) to music.
Most Masses are settings of the liturgy in Latin, the traditional language of the Roman Catholic Church, but there are a significant number written in the languages of non-Catholic countries where vernacular worship has long been the norm. For example, there are many Masses (often called "Communion Services") written in English for the Church of England.
Masses can be a cappella, for the human voice alone, or they can be accompanied by instrumental obbligatos up to and including a full orchestra. Many Masses, especially later ones, were never intended to be performed during the celebration of an actual mass.
Generally, for a composition to be a full Mass, it must contain the following six sections, which together constitute the Ordinary of the Mass:
1. Kyrie Eleison (from the Greek-Lord, have mercy)
2. Gloria (Glory to God in the Highest)
3. Credo (I Believe)
4. Sanctus (Holy)
5. Benedictus (Blessing)
6. Agnus Dei (Lamb of God)
