Gradual

[2] In the Tridentine Mass, it is sung after the reading or chanting of the epistle and before the Alleluia, or, during penitential seasons, before the tract.

Although the Gradual remains an option in the Mass of Paul VI, its use is extremely rare[citation needed] outside monasteries.

Responsorial chants derive from early Christian traditions of singing choral refrains called responds between psalm verses.

According to the Catholic Encyclopedia, it (and the associated Alleluia or Tract) is the oldest of the chants of the Proper of the Mass, and, in contrast to the Introit, Offertory, and Communion, the only one that was not sung to accompany some other liturgical action, historically a procession.

[1] However, early sources use the form gradale ("graded" or "distinguished"), and the Alia Musica (c. 900) uses the term antiphona gradalis for the Introit.

In Eastertide, the Gradual is normally omitted, and a second Alleluia is sung in its place, except within the Octave of Easter.

The present Ambrosian Rite sometimes has a Prophecy before the Epistle, in which case there follows the Psalmellus, two or three verses from a psalm, which corresponds to the Gradual.

Graduals are among the most florid and melismatic of all Gregorian chants; Clamaverunt iusti, for example, has melismas with up to 66 notes.

[3] Graduals as a group are also notable for melismas that stress one or two pitches, both through repeated notes and repercussive neumes.

[4] Like Tracts, most Graduals show clear signs of centonization, a process of composition in which an extended vocabulary of stock musical phrases are woven together.

In 1198, Odo de Sully, Bishop of Paris, authorized polyphonic performances of Graduals, including Pérotin's famous four-part organa, Sederunt principes for St. Stephen's Day and Viderunt omnes for Christmas.

A Gradual is generally distinguished from the Missal by omitting the spoken items, and including the music for the sung parts.