This Class III feast is celebrated on November 27 at the pleasure of the local ordinary, as it is a devotion and not a universal feast.
From the 1945 Marian Missal and 1913 Catholic Encyclopedia:
The devotion commonly known as that of the Miraculous Medal owes its origin to Zoe Labore, a member of the Daughters of Charity of St. Vincent de Paul, known in religion as Sister Catherine Labouré who was subsequently canonized. It was she to whom the Blessed Virgin Mary appeared three separate times in the year 1830, at the mother-house of the community at Paris on Rue du Bac. The first of these apparitions occurred 18 July, the second 27 November, and the third a short time later. On the second occasion, Sister Catherine records that the Blessed Virgin appeared as if standing on a globe, and bearing a globe in her hands. As if from rings set with precious stones dazzling rays of light were emitted from her fingers. These, she said, were symbols of the graces which would be bestowed on all who asked for them. Sister Catherine adds that around the figure appeared an oval frame bearing in golden letters the words “O Mary, conceived without sin, pray for us who have recourse to thee”; on the back appeared the letter M, surmounted by a cross, with a crossbar beneath it, and under all the Sacred Hearts of Jesus and Mary, the former surrounded by a crown of thorns, and the latter pierced by a sword.
At the second and third of these visions a command was given to have a medal struck after the model revealed, and a promise of great graces was made to those who wear it when blessed. After careful investigation, Fr. Aladel, the spiritual director of Sister Catherine, obtained the approval of Monsignor de Quelen, Archbishop of Paris, and on June 30, 1832, the first medals were struck and with their distribution the devotion spread rapidly. One of the most remarkable facts recorded in connection with the Miraculous Medal is the conversion of a Jew, Alphonse Ratisbonne of Strasburg, who had resisted the appeals of a friend to enter the Church. Ratisbonne consented, somewhat reluctantly, to wear the medal, and being in Rome, he entered, by chance, the church of Sant’ Andrea delle Fratte and beheld in a vision the Blessed Virgin exactly as she is represented on the medal; his conversion speedily followed. This fact has received ecclesiastical sanction, and is recorded in the office of the feast of the Miraculous Medal.
In 1847, Fr. Etienne, superior-general of the Congregation of the Mission, obtained from Pope Pius IX the privilege of establishing in the schools of the Sisters of Charity a confraternity under the title of the Immaculate Conception, with all the indulgences attached to a similar society established for its students at Rome by the Society of Jesus. This confraternity adopted the Miraculous Medal as its badge, and the members, known as the Children of Mary, wear it attached to a blue ribbon. On July 23, 1894, Pope Leo XIII, after a careful examination of all the facts by the Sacred Congregation of Rites, instituted a feast, with a special Office and Mass, of the Manifestation of the Immaculate Virgin under the title of the Miraculous Medal.
The Introit is from Exodus 13:9. The Collect is as follows:
|Oremus. Dómine Jesu Christe, qui beatíssimam Vírginem Maríam Matrem tuam ab orígine immaculátam innúmeris miráculis claréscere voluísti: concéde; ut ejúsdem patrocínium semper implorántes, gaudia consequámur aetérna. Qui vivis et regnas, cum Deo Patre in unitáte Spíritu Sancti, Deus, Per omnia saecula saeculorum. R. Amen.||Let us pray.
O Lord Jesus Christ, Who hast willed that the most blessed Virgin Mary, Thy mother, sinless from the first moment of her conception, should be glorified by countless miracles: grant that we, who never cease from imploring her patronage, may attain in the end to eternal happiness. Who livest and reignest, with God the Father, in the unity of the Holy Ghost, God,
Forever and ever.