Gregorian chant
Gregorian chant is named after St. Gregory I the Great (pope 590-604). It was collected and codified during his reign. Charlemagne, king of the Franks (768-814), imposed Gregorian chant on his kingdom, where another liturgical tradition--the Gallican chant--was in common use.

Gregorian chant, monophonic, liturgical music of the Roman Catholic Church, used to accompany the text of the mass and the divine office in Latin.

The Ordinary of the mass includes the Kyrie , Gloria, Credo, Sanctus, Benedictus, Agnus Dei. And the Proper of the mass is composed of the Introit, Gradual, Alleluia, sequence and Offertory.

The divine office consists of eight prayer services: Matins, Lauds, Prime, Terce, Sext, None, Vespers, and Compline. Each includes antiphons or refrains, short texts that precede or follow each psalm and are set mostly in syllabic chant.