Eight days before Christmas, in memory of the Annunciation

This Feast, which is now kept, not only throughout the whole of Spain, but in almost all the Churches of the Catholic world, owes its origin to the Bishops of the Tenth Council of Toledo, in 656.

These Prelates having thought that there was an incongruity in the ancient practice of celebrating the feast of the Annunciation on the 25th of March, inasmuch as this joyful solemnity frequently occurs at the time when the Church is intent upon the Passion of our Lord, and is sometimes obliged to be transferred into Easter Time, with which it is out of harmony for another reason—they decreed that, henceforth, in the Church of Spain there should be kept, eight days before Christmas, a solemn Feast with an Octave, in honor of the Annunciation, and as a preparation for the great solemnity of our Lord's Nativity.

In course of time, however, the Church of Spain saw the necessity of returning to the practice of the Church of Rome, and of those of the whole world, which solemnize the 25th of March as the day of our Lady's Annunciation and the Incarnation of the Son of God. But such had been, for ages, the devotion of the people for the Feast of the 18th of December, that it was considered requisite to maintain some vestige of it. They discontinued, therefore, to celebrate the Annunciation on this day; but the faithful were requested to consider, with devotion, what must have been the sentiments of the Holy Mother of God during the days immediately preceding her giving him birth.

A new Feast was instituted, under the name of the Expectation of the Blessed Virgin. This Feast, which sometimes goes under the name of Our Lady of O, or the Feast of O, on account of the Great Antiphons which are sung during these days, and, in a special manner, of that which begins O Virgo Virginum (which is still used in the Vespers of the Expectation, together with the O Adonaï, the Antiphon of the Advent Office,) - is kept with great devotion.

O Virgin of virgins! How shall this be? For never was there one like Thee, nor will there ever be. Ye daughters of Jerusalem, why look ye wondering at Me? What you behold is a divine mystery.

Adapted from The Liturgical Year by Abbot Guéranger of Solesmes