A musical theatre work composed by Leonard Bernstein. Commissioned by Jacqueline Kennedy, it premiered on September 8, 1971, conducted by Maurice Peress.
Originally, Bernstein had intended to compose a traditional Mass, but instead decided on a more innovative form. The work is based on the Tridentine Mass of the Roman Catholic Church. Although the liturgical passages are sung in Latin, Mass also includes additional texts in English written by Bernstein, Broadway composer Stephen Schwartz, and Paul Simon (who wrote the first quatrain of the trope "Half of the People"). The work is intended to be staged theatrically, but it has also been performed in a standard concert setting.
In the beginning all of the performers are in harmony and agreement. During the course of the Mass, however, the street choir begins expressing doubts and suspicions about the necessity of God in their lives and the role of the Mass itself. At the play's emotional climax, the growing cacophony of the chorus' complaining finally interrupts the elevation of the Body and Blood (the consecrated bread and wine). The celebrant, in a furious rage, hurls the sacred bread, housed in an ornate cross-like monstrance, and the chalice of wine, smashing them on the floor. At this sacrilege the other cast members collapse to the ground as if dead while the Celebrant sings a solo. This solo blends the chorus's disbelief with his realization that he feels worn out and wonders where the strength of his original faith has gone. At the end of his song, he too collapses. A bird-like (Holy Spirit) flute solo begins, darting here and there from different speakers in the hall, finally "alighting" in a single clear note. An altar server, who was absent during the conflict, then sings a hymn of praise to God, "Sing God a Secret Song". This restores the faith of the three choirs, who join the altar server, one by one, in his hymn of praise. They tell the Celebrant "Pax tecum" (Peace be with you), and end with a hymn asking for God's blessing. As in the actual Mass, the last words of the piece are: "The Mass is ended; go in peace."