All sources at least give two central messianic proclamations, with the voice of prophecy speaking through the Psalmist: 'The Lord said to me, 'You are my son, and this day have I begotten you ' Why do the nations rage, and the people meditate on folly?' (Ps. Not only are both 'responses' and 'verses' taken from the same Psalm, but numerous sources also preserve more complete versions of the chant, including several rounds of alternation. It is the Introit Dominus dixit ad me.Īll Catholic Introit chants serve as music for the processional entrance of the clergy, and originally made up a series of responsory verses alternating with verses from a Psalm Dominus dixit ad me retains much of this earliest character.

The first Mass, celebrated at midnight on Christmas Eve to mark the very hour of His coming and of the angel's annunciation to the shepherds, begins in just this fashion, with an Introit that quotes the powerful messianic texts of the second Psalm. The Christian Church responded by initiating a threefold celebration of Christ's incarnation on December 25, with texts and music in each of the three Masses that highlight the kingly power of the Christian god Jesus, and of the light that Christians believe came into the world at His birth. One strong impetus for the codification of the Christmas celebration seems to have been a reaction against the pagan emperor Aurelian's proclamation of December 25, the winter solstice, as a festival to the sun-god.

The observance of Christmas Day was the first annual feast of the medieval church, beginning in the fourth century the Christmas liturgy is younger than Easter by 200 years and even predates the prescribed celebration of Sundays by 300.