Understanding Classical Music – The Mass

In most survey courses of Western music, the earliest music studied is Gregorian Chant. These single-voiced compositions were the official music of the Roman Catholic Church during the Middle Ages and were grouped according to the season of the year that they would be sung. Chants were the basic elements of the musical portion of the mass – the church service.
When discussing the elements of the mass, the chants fall into one of two categories: the Mass Ordinary and the Mass Proper. The Mass Ordinary were those chants that consistently appeared daily as part of the mass, regardless of the church holiday that was being celebrated. Five chants made up the Mass Ordinary: Kyrie ("God have mercy"); Agnus Dei ("Lamb of God who takes away the sin of the world"); Sanctus ("Holy, Holy, Holy"); Gloria ("Glory to God in the highest"); and Credo ("Apostle's Creed"). Other chants that appeared in the mass varied daily and were determined by the Church calendar. These daily changing portions of the mass comprised the Mass Proper.
It was Guillaume de Machaut who first raised the standard of the Mass as a musical form. Machaut's Notre Dame Mass was the first polyphonic setting of the Mass Ordinary. In other words, Machaut composed music for all five sections of the Mass Ordinary to be sung by multiple voices of equal importance (polyphony). This first significant Mass setting, like most of the others composed during the Medieval and Renaissance periods, were written for a cappella voices.
What began with Machaut became a long standing tradition in Classical music. Many of the greatest composers of Western Music such as Palestrina, Bach, Mozart, Schubert, and Brahms would add their compositions to the opus of Mass settings. Over the centuries, the Mass became more complex, growing from its relatively simple a cappella beginnings to include the full power and grandeur of the symphony orchestra accompanying massive choirs.