Mass

In music, a setting of the music for the main service of the Roman Catholic Church. The items of the Mass are sung in Latin and fall into two groups: the Ordinary (the items of the Mass are invariable, regardless of day or season) consists of the Kyrie, Gloria, Credo, Sanctus with Benedictus, and Agnus Dei; the Proper (the items of the Mass are ‘proper’ to the day or season) consists of additional matter namely the Introit, Gradual, Alleluia or Tract, Offertory, and Communion). A notable example of the Ordinary of the Mass is J S Bach's Mass in B Minor (about 1748).

The medieval practice of writing the movements of a Mass on plainsong melodies, sung by the tenor, was soon extended to the employment of secular tunes. L'Homme armé on the continent and The Western Wind in England, for example, were especially favoured for this purpose. In the course of the 16th century, however, more and more composers wrote wholly original Masses, though the practice of borrowing material from motets or chansons was also common. Even in later times the treatment of the Mass remained essentially polyphonic, though not necessarily throughout. Certain portions, ‘Et vitam venturi saeculi’ at the end of the Credo, were almost always set as fugues. Major examples are Wolfgang Amadeus Mozart's Requiem (1791), Ludwig van Beethoven's Missa solemnis (1819-22), and György Ligeti's Requiem (1963-65.