The Mass

The music of the Mass consists of two main groups of pieces; the Ordinary (the texts sung at each service), and the Proper (those which change according to the season or saint being celebrated). The repeated use of the texts of the Ordinary chants at every Mass suggests that they may have been the original people's part. Of the melodies for these texts that have come down to us, some are simple enough to serve this purpose, and others are more ornate. The pieces which constitute the Ordinary are:

The Chants of the Proper are: These chants suggest performance by different groups of people. The Introits and Communions may have been sung by a choir, whereas the Graduals, Alleluias and Tracts (sung between the Readings), together with the Offertories, are melodically the most ornate part of the repertory for the Mass, and were perhaps intended to be sung by soloists or by a small group. Apart from these two main groups of sung pieces, other parts of the service are also chanted to simple inflexions (also known as cantillation): the prayers, the readings and the Eucharistic Prayer. The Lord's Prayer is always sung to a simple melody (formerly by the priest alone) which is suitable for congregational use.

Click here to see examples of these genres of chant.
Click here to listen to some examples of the chant.
Click here to read about Chant Books in Latin for the Mass

from The Gregorian Association web site:  http://www.beaufort.demon.co.uk/chant.htm.

The page also contains many other useful short articles and several valuable links to sites about chant.