Editing Gregorian chant (section)

==Liturgical functions==
Gregorian chant is sung in the Office during the [[canonical hours]] and in the liturgy of the [[Mass (liturgy)|Mass]]. Texts known as ''[[Accentus Ecclesiasticus|accentus]]'' are intoned by bishops, priests, and deacons, mostly on a single [[reciting tone]] with simple melodic formulae at certain places in each sentence. More complex chants are sung by trained soloists and choirs. The [[Graduale Romanum]] contains the proper chants of the Mass (i.e., Introit, Gradual, Alleluia, Tract, Offertory, Communion) and the complete [[Kyriale]] (the collection of Mass Ordinary settings). The ''[[Liber usualis]]'' contains the chants for the [[Graduale Romanum]] and the most commonly used Office chants.

===Proper chants of the Mass===
The Introit, Gradual, Alleluia, Tract, Sequence, Offertory and Communion chants are part of the [[Proper (liturgy)|Proper]] of the Mass. "Proprium Missae" in Latin refers to the chants of the Mass that have their proper individual texts for each Sunday throughout the annual cycle, as opposed to 'Ordinarium Missae' which have fixed texts (but various melodies) (Kyrie, Sanctus, Benedictus, Agnus Dei).

[[Introit]]s cover the procession of the officiants. Introits are antiphonal chants, typically consisting of an antiphon, a psalm verse, a repeat of the antiphon, an intonation of the Gloria Patri [[Doxology]], and a final repeat of the antiphon. [[Reciting tone]]s often dominate their melodic structures.

[[Gradual]]s are responsorial chants that follow the reading of the [[Epistle]]. Graduals usually result from ''[[centonization]]''; stock musical phrases are assembled like a patchwork to create the full melody of the chant, creating families of musically related melodies. Graduals are accompanied by an elaborate Verse, so that it actually consists in two different parts, A B. Often the first part is sung again, creating a 'rondeau' A B A. At least the verse, if not the complete gradual, is for the solo cantor and are in elaborate, ornate style with long, wide-ranged melismata.

The [[Alleluia]] is known for the ''[[jubilus]]'', an extended joyful melisma on the last vowel of 'Alleluia'. The Alleluia is also in two parts, the alleluia proper and the psalmverse, by which the Alleluia is identified (Alleluia V. Pascha nostrum). The last melisma of the verse is the same as the jubilus attached to the Alleluia. Alleluias are not sung during penitential times, such as [[Lent]]. Instead, a [[Tract (liturgy)|Tract]] is chanted, usually with texts from the Psalms.

[[Sequence (poetry)|Sequences]] are sung poems based on couplets. Although many sequences are not part of the liturgy and thus not part of the Gregorian repertory proper, Gregorian sequences include such well-known chants as ''[[Victimae paschali laudes]]'' and ''[[Veni Sancte Spiritus]]''. According to [[Notker Balbulus]], an early sequence writer, their origins lie in the addition of words to the long melismata of the jubilus of Alleluia chants.{{sfn|Crocker|1977|pp=1–2}}

===Ordinary chants of the Mass===
The Kyrie, Gloria, Credo, Sanctus, Benedictus and Agnus Dei use the same text in every service of the Mass. Because they follow the regular invariable "order" of the Mass, these chants are called "[[Ordinary of the Mass|Ordinary]]".

The [[Kyrie]] consists of a threefold repetition of "Kyrie eleison" ("Lord, have mercy"), a threefold repetition of "Christe eleison" ("Christ have mercy"), followed by another threefold repetition of "Kyrie eleison." In older chants, "Kyrie eleison imas" ("Lord, have mercy on us") can be found. The Kyrie is distinguished by its use of the [[Hellenistic Greek|Greek language]] instead of Latin. Because of the textual repetition, various musical repeat structures occur in these chants. The following, Kyrie ad. lib. VI as transmitted in a Cambrai manuscript, uses the form ABA CDC EFE', with shifts in [[tessitura]] between sections. The E' section, on the final "Kyrie eleison", itself has an aa'b structure, contributing to the sense of climax.{{sfn|Hiley|1995|p=153}}

{{Listen|type=music|filename=Kyrie 55, Vatican ad lib. VI, Cambrai.ogg|title=Kyrie 55, Vatican ad lib. VI, from Cambrai, Bibl. Mun. 61, fo.155v|description=As transcribed by [[David Hiley]]; example of musical repeat structures in Gregorian chant}}
The [[Gloria in excelsis Deo|Gloria]] recites the Greater [[Doxology]], and the [[Credo]] intones the [[Nicene Creed]]. Because of the length of these texts, these chants often break into musical subsections corresponding with textual breaks. Because the Credo was the last Ordinary chant to be added to the Mass, there are relatively few Credo melodies in the Gregorian corpus.

The [[Sanctus]] and the [[Agnus Dei (music)|Agnus Dei]], like the Kyrie, also contain repeated texts, which their musical structures often exploit.

Technically, the [[Ite missa est]] and the [[Benedicamus Domino]], which conclude the Mass, belong to the Ordinary. They have their own Gregorian melodies, but because they are short and simple, and have rarely been the subject of later musical composition, they are often omitted in discussion.

[[File:Salve Regina.png|thumb|left|Plainchant notation for the solemn setting of the [[Salve Regina]]; a simple setting is used more commonly.]]

===Chants of the Office===
Gregorian chant is sung in the [[canonical hours]] of the [[monastic]] Office, primarily in antiphons used to sing the [[Psalms]], in the Great [[Responsory|Responsories]] of [[Matins]], and the Short Responsories of the Lesser Hours and [[Compline]]. The psalm antiphons of the Office tend to be short and simple, especially compared to the complex Great Responsories.

At the close of the Office, one of four ''[[Marian antiphon]]s'' is sung. These songs, ''Alma Redemptoris Mater'' (see top of article), ''Ave Regina caelorum'', ''Regina caeli laetare'', and ''Salve, Regina'', are relatively late chants, dating to the 11th century, and considerably more complex than most Office antiphons. [[Willi Apel]] has described these four songs as "among the most beautiful creations of the late Middle Ages".{{sfn|Apel|1990|p=404}}

{{listen|type=music|filename=Alma Redemptoris Mater.ogg|title=Alma Redemptoris Mater|description=Marian antiphon sung at Compline and Lauds between the First Sunday of Advent and Candlemas|format=[[Ogg]]}}