Church music is music written for performance in church, or any musical setting of ecclesiastical liturgy, or music set to words expressing propositions of a sacred nature, such as a hymn.
Christianity began as a small, persecuted Jewish sect. At first there was no break with the Jewish faith; Christians still attended synagogues and the Temple in Jerusalem just as Christ had done, and presumably still carried on the same musical traditions in their separate Christian meetings. The only record of communal song in the Gospels is the last meeting of the disciples before the Crucifixion. Outside the Gospels, there is a reference to St. Paul encouraging the Ephesians and Colossians to use psalms, hymns and spiritual songs.
Later, there is a reference in Pliny who writes to the emperor Trajan (61–113) asking for advice about how to prosecute the Christians in Bithynia, and describing their practice of gathering before sunrise and repeating antiphonally "a hymn to Christ, as to God". Antiphonal psalmody is the singing or musical playing of psalms by alternating groups of performers. The peculiar mirror structure of the Hebrew psalms makes it likely that the antiphonal method originated in the services of the ancient Israelites. According to the historian Socrates of Constantinople, its introduction into Christian worship was due to Ignatius of Antioch (died 107), who in a vision had seen the angels singing in alternate choirs.
The use of instruments in early Christian music seems to have been frowned upon. In the late 4th or early 5th century St. Jerome wrote that a Christian maiden ought not even to know what a lyre or flute is like, or to what use it is put. The introduction of church organ music is traditionally believed to date from the time of the papacy of Pope Vitalian in the 7th century.