attract new members to the Church. Music is an integral part of mass. It accompanies various rituals acts and contributes to the totality of worship service. Music in mass is an activity that participants share with others in the celebration of Jesus Christ. 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 invariable five sections, which together constitute the Ordinary of the Mass. Kyrie ("Lord have mercy") Gloria ("Glory be to God on high") Credo ("I believe in one God"), the Nicene Creed Sanctus ("Holy, Holy, Holy"), the second part of which, beginning with the word "Benedictus" ("Blessed is he"), was often sung separately after the consecration, if the setting was long. (See Benedictus for other chants beginning with that word.) Agnus Dei ("Lamb of God") This setting of the Ordinary of the Mass spawned a tradition of Mass composition to which many famous composers of the standard concert repertory made contributions, including Bach, Haydn, Mozart and Beethoven. The Requiem Mass, or the Mass of the Dead, is a modified version of the ordinary mass. Musical settings of the Requiem mass have a long tradition in Western music. There are many notable works in this tradition, including those by Ockeghem, Pierre de la Rue, Brumel, Jean Richafort, Pedro de Escobar, Antoine de Févin, Morales, Palestrina, Tomás Luis de Victoria, Mozart, Gossec, Cherubini, Berlioz, Brahms, Bruckner, Dvořák, Frederick Delius, Maurice Duruflé, Fauré, Liszt, Verdi, Herbert Howells, Stravinsky, Britten, György Ligeti, Penderecki, Henze, and Andrew Lloyd Webber. In a liturgical mass, there are variable other sections that may be sung, often in Gregorian chant. These sections, the "proper" of the mass, change with the day and season according to the church calendar, or according to the special circumstances of the mass. The proper of the mass is usually not set to music in a mass itself, except in the case of a Requiem Mass, but may be the subject of motets or other musical compositions. The sections of the proper of the mass include the introit, gradual, Alleluia or Tract (depending on the time of year), offertory and communion. Carols A carol is a