Introit

An introit is a piece of music played or sung at the beginning of a worship service. In the traditional Roman Catholic Mass, the introit is the first part of the proper, consisting of an antiphon, a psalm verse, and the Gloria Patri.1

Gregorian chant, a form of liturgical music of the Roman Catholic Church, often accompanies the text of the mass and the divine office. The introit, in this context, is a processional chant that originally included a psalm with a refrain. By the 9th century, it evolved into its present form: a refrain in a neumatic style, followed by a psalm verse in psalm-tone style, and then the refrain repeated.2