Question: Were "First Saturdays" observed prior to the revelations at Fatima? (CSG)
Answer: Saturdays have been associated with devotion to the Blessed Virgin for the past ten or twelve centuries, although no one seems to know exactly how the connection began.
The Roman Missal contains five Mass formulas for use on Saturdays during the various seasons of the year. They are to be said whenever a "simple" or "4th class" feast falls on Saturday, and many diocesan calendars displace even higher class feasts on the First Saturday of the month. There are also a number of Masses that are appointed for specific Saturdays of the year -- for example, Our Lady Queen of the Apostles on the Saturday after the Ascension, and Our Lady of Consolation on the Saturday following the feast of St. Augustine. We know that Saturday Masses of the Blessed Virgin go back at least to the Leofric Missal, in use in pre-conquest Anglo Saxon England.1
The Sabbatine privilege grants to those who wear the Brown Scapular, pray the Little Office, and observe chastity according to their state in life, the assurance that the Blessed Virgin will deliver them from Purgatory on the First Saturday after their death. The privilege, of course, predates its approval by Pope John XXII in the fourteenth century.
On July 1st, 1905, Pope St. Pius X granted a plenary indulgence to those who "spend some time in devout prayers or meditations in honor of the Blessed Virgin Mary Immaculate, on the first Saturday or Sunday of each month with the intention of persevering in the same practice for the space of twelve months," on the condition of Confession, Holy Communion, and prayers for the Pope.2 A second indulgence was granted on June 13th, 1912 "to the faithful who on the First Saturday of each month perform some special exercise of devotion in honor of the Blessed Virgin Mary Immaculate, in order to make atonement for the blasphemies whereby the name and prerogatives of the same Blessed Virgin are reviled may gain a plenary indulgence" on the condition of Confession, Holy Communion, and prayers for the Pope.3 Some time prior to the publication of the Fatima revelations, Pope Benedict XV added to Pope St. Pius' grant "a plenary indulgence at the hour of death, if after Confession and Communion, or at least being duly contrite, they invoke with their lips if possible, otherwise in their hearts, the most holy Name of Jesus, and accept death with resignation from the hand of God as the due punishment for their sins" on the condition of making the devotion on eight successive first Saturdays.4 (Note that the indulgences mentioned in this paragraph do not appear to be among those granted by Pope Paul VI in the 1968 Enchiridion of Indulgences.)
One can certainly see the similarity of these grants of indulgence to the promises attributed to our Lady at Fatima on July 13th, 1917. Of course no one should be surprised to learn of our Lady ratifying the acts of the holy Pope St. Pius.
1. Catholic Encyclopedia, s.v. "Virgin."
2. Raccolta #365.
3. Raccolta #367.
4. Ibid., November 9th, 1920.