Mass Proper
The chants of the Mass that change with the church year.
What it means
The Proper of the Mass comprises the parts of the Catholic Mass whose texts and chants change according to the feast day or season of the church year. They include the Introit (entrance chant), the Gradual, the Alleluia or Tract, the Offertory (preparation of the gifts) and the Communion. In contrast stand the unchanging parts of the Ordinary, such as the Kyrie and Gloria.
Musical use
In Gregorian chant the Proper chants are a core repertory: every Sunday and feast day has its own melodies and texts, mostly from the Psalms. Heinrich Isaac set the Proper polyphonically in the Choralis Constantinus (c. 1508–1517), William Byrd in his Gradualia (1605/1607). Later usually only the parts of the Ordinary were set, because they recur in every Mass.
The Proper should be distinguished from the Ordinary, whose five parts are always the same, and from the Requiem, which has its own Proper with its own chants for the Mass for the dead.
Performance practice
When you sing Proper chants, find out about the feast day, since text and melody belong to the day. Note the changing moods of the church year, from Advent to Easter, and shape the sound accordingly.