The Nativity of the Lord (Christmas)

Solemnity, Holy Day of Obligation

Feast Day

December 25

The Solemnity of the Nativity of the Lord celebrates the birth in time of the eternal Son of God, the Word made flesh. The date of December 25 is documented in the Latin West by the Chronograph of 354, which lists December 25 as the natalis Christi, and is firmly established by the late fourth century in both Rome (under Pope Saint Damasus I) and the Christian East (in most regions; the Armenian Church retains the older common celebration of Nativity and Epiphany on January 6). Two ancient explanations of the date are given: the so-called calculation hypothesis, which dates the Annunciation to March 25 (the spring equinox under the Julian calendar, also identified as the date of the Crucifixion) and the Nativity nine months later; and the influence of the Roman feast of Sol Invictus on December 25, against which Christians proclaimed Christ as the true Sun of Righteousness, sol iustitiae (Malachi 4:2).

The Roman Missal provides four distinct Mass formularies for the Solemnity: the Vigil Mass on the evening of December 24; the Mass during the Night (popularly called Midnight Mass); the Mass at Dawn; and the Mass during the Day. The Gospel readings traverse the mystery from the announcement of the angel and the birth at Bethlehem (Luke 2 at the Vigil, Night, and Dawn Masses) to the Prologue of John (1:1-18), proclaimed at the Mass during the Day, in which the Church confesses the eternal divinity of the Word who is now incarnate. December 25 is a Holy Day of Obligation throughout the Latin Church and begins the Octave of Christmas, which closes on January 1, the Solemnity of Mary, Mother of God. Christmas Time, in the reformed calendar, extends from First Vespers of Christmas to the Sunday after the Epiphany, the Feast of the Baptism of the Lord.