Gregorian chantGregorian chant is the central tradition of Western plainchant, a form of monophonic, unaccompanied sacred song in Latin (and occasionally Greek) of the Roman Catholic Church. Gregorian chant developed mainly in western and central Europe during the 9th and 10th centuries, with later additions and redactions. Although popular legend credits Pope Gregory I with inventing Gregorian chant, scholars believe that it arose from a later Carolingian synthesis of the Old Roman chant and Gallican chant.
Canonical hoursIn the practice of Christianity, canonical hours mark the divisions of the day in terms of fixed times of prayer at regular intervals. A book of hours, chiefly a breviary, normally contains a version of, or selection from, such prayers. In the Roman Rite of the Catholic Church, canonical hours are also called officium, since it refers to the official prayer of the Church, which is known variously as the officium divinum ("divine service" or "divine duty"), and the opus Dei ("work of God").
PlainsongPlainsong or plainchant (calque from the French plain-chant; cantus planus) is a body of chants used in the liturgies of the Western Church. When referring to the term plainsong, it is those sacred pieces that are composed in Latin text. Plainsong was the exclusive form of Christian church music until the ninth century, and the introduction of polyphony. The monophonic chants of plainsong have a non-metric rhythm. Their rhythms are generally freer than the metered rhythm of later Western music, and they are sung without musical accompaniment.
Holy WeekHoly Week (Ἁγία καὶ Μεγάλη Ἑβδομάς) is the most sacred week in the liturgical year in Christianity. For all Christian traditions it is a moveable observance. In Eastern Christianity, which also calls it Great Week, it is the week following Great Lent and Lazarus Saturday, starting on the evening of Palm Sunday and concluding on the evening of Great Saturday. In Western Christianity, Holy Week is the sixth and last week of Lent, beginning with Palm Sunday and concluding on Holy Saturday.