The Date of Christmas
Ten years after the eastern patriarchate of Antioch began celebrating the feast of Christmas on December 25, Saint John Chrysostom in a homily to his congregation said that the Western churches had from the very commencement of Christianity kept it on this day. Moreover, the holy doctor provided arguments for this date drawn from reason and from Scripture.
As Abbot Prosper Gueranger, O.S.B. writes in his Liturgical Year, volume 3, page 2, Saint John declared that "the Church of Rome had every means of knowing the true day of our Savior's birth, since the acts of Enrollment, taken in Judea by command of Augustus (Luke 2:3-5) were kept in the public archives of Rome." In arguing from Scripture, Gueranger continues, Saint John "reasons thus: we know from the Sacred Scriptures that it must have been in the fast of the seventh month that the priest Zachary had the vision in the temple (cf: Leviticus 23:24: 'The tenth day of the seventh month is the day of Atonement when you shall. . .offer an oblation to the Lord" -- the seventh month corresponds to the end of September and the beginning of October); after which Elizabeth, his wife, conceived John the Baptist; hence it follows that the Blessed Virgin Mary, having, as the Evangelist Saint Luke relates, received the Angel Gabriel's visit, and conceived the Savior of the word in the sixth month of Elizabeth's pregnancy, that is to say in March, the birth of Jesus must have taken place in the month of December."