Image Source. Notice on the altar it is written "Hic Verbum Caro Factum Est" (The Word was made flesh HERE)
This feast is not one of those inserted in the universal calendar of the Church; but it is kept throughout Italy, and in many dioceses in various parts of the Christian world, and by a number of religious Orders. It was instituted in thanksgiving for the great favour bestowed on the western Church, whereby God, to console Christians for the loss of the holy sepulchre, miraculously translated into a Catholic land the humble yet ever venerable house, in which Mary received the message of the angel, and where, by the consent of this holy Virgin, the Word was made flesh and began to dwell among us. It is no unusual thing to meet with Catholics, who are sincerely devoted to their holy faith, yet who have never heard of the house of Loretto. It is for their sake that we have resolved to take the opportunity of this feast to give an exact and concise account of this wonderful event."
Msgr. Paul Guérin gives the following detailed account of this miraculous translation:
Towards the end of the thirteenth century, the terrible news reached Europe that the Holy Land was lost to the Christians, who during two centuries had been able to maintain the Latin kingdom there by virtue of their repeated Crusades. But at the time the Church was deploring this painful loss, a new joy was given them: the holy house of Nazareth — site of the birth of the Mother of God, of Her early education and of the Annunciation by the Angel Gabriel of the wondrous news of the Incarnation of the Son of God — had been found, transported miraculously, near Tersatz in Dalmatia (Yugoslavia) on May 10th of the year 1291.
Between Tersatz and nearby Fiume, the residents of the region beheld one morning an edifice, in a location where never had any been seen before. After the residents of the region talked among themselves of the remarkable little house surmounted by a bell tower, and which stood without foundations on the bare ground, describing its altar, an ancient statue of Our Lady, and other religious objects which their wondering eyes had seen within it, another surprise came to astound them once more.
Their bishop suddenly appeared in their midst, cured from a lingering illness which had kept him bedridden for several months. He had prayed to be able to go see the prodigy for himself, and the Mother of God had appeared to him, saying, in substance: “My son, you called Me; I am here to give you powerful assistance and reveal to you the secret you desire to know. The holy dwelling is the very house where I was born... It is there that when the announcement was brought by the Archangel Gabriel, I conceived the divine Child by the operation of the Holy Spirit. It is there that the Word was made flesh! After My decease, the Apostles consecrated this dwelling, illustrated by such elevated mysteries, and sought the honor of celebrating the August Sacrifice there. The altar is the very one which the Apostle Saint Peter placed there. The crucifix was introduced by the Apostles, and the cedar statue is My faithful image, made by the hand of the Evangelist Saint Luke... Your sudden return to health from so long an illness will bear witness to this prodigy.”
Nicolas Frangipane, governor of the territory of Ancona, was absent, but when the news was carried to him, he returned from a war in order to verify its authenticity. He sent to Nazareth, at the eastern limits of the Mediterranean Sea, the bishop and three other persons, to examine the original site of the house. Indeed the house was no longer there, but its foundations remained and were found conformable in every detail of dimension and substance, to the stones at the base of the house now in Dalmatia. The testimony of the delegates was drafted according to legal formalities, and confirmed by a solemn oath.
Then, after three years spent in Dalmatia, the house disappeared. Paul Della Selva, a holy hermit of that period and of the region of Ancona, wrote: “During the night of December 10th, a light from heaven became visible to several inhabitants of the shores of the Adriatic Sea, and a divine harmony woke them that they might contemplate a marvel exceeding all the forces of nature. They saw and contemplated a house, surrounded by heavenly splendor, transported through the air.” The angelic burden was brought to rest in a forest, where again the local residents were able to contemplate the signal relics which it contained. The antique Greek crucifix mentioned by Our Lady was made of wood, and attached to it was a canvas on which the words Jesus of Nazareth, King of the Jews, were painted. The cedar statue of the Virgin had been painted also; she wore a red robe and a blue cloak and held the Infant Jesus in Her arms. His right hand was raised in blessing; His left hand held a globe, symbol of His sovereign power.
The story was far from ended. The house moved again, after robbers began to intercept pilgrims coming through the forest to visit the marvel. Twice more it rose from its place, the first time coming to rest on a private terrain, which became then a source of dispute between two brothers; and finally on a hilltop where a dusty and uneven public road became its permanent site. For centuries the people of Dalmatia came across the sea on pilgrimage, often crying out to Our Lady and Her House to come back to them! Finally in 1559, after one such visit by 300 pilgrims, the Sovereign Pontiff had a hospice built at Loreto for families who preferred to remain near the house, rather than return to a land deprived of its sacred presence.
The reddish-black stones of the house are a sort entirely foreign to Italy; the mortar cementing them is again entirely different from the volcanic-ash-based substance used in that country. The residents of the region put up a heavy brick wall to support the house, which was exposed to the torrential rains and winds of the hilltop and was completely without foundation. But no sooner was that wall completed, than they came back one morning to find it had moved away from the house, as if to express its reverence, to a distance which permitted a small child to walk around it with a torch in hand. The Author of the miracle wanted it to be well understood that He who had brought it without human assistance, was capable also of maintaining it there where He had placed it, without human concourse.
The episodes concerning the Translation of the Holy House, all duly verified, were consigned in documents borne to Rome to the Sovereign Pontiffs at various epochs. Pope Sixtus IV declared that the house was the property of the Holy See, and assigned duties to a specified personnel named to be its custodians. By Pope Leo X the indulgence applicable to the visit of several churches of Rome was accorded also to a pilgrimage to Loreto. Eventually a magnificent basilica was built around the house, which within the basilica was itself enhanced by a white marble edicule. Pope Clement IX in 1667, placed the story of the House in the Roman Martyrology for the 10th of December under the title: At Loreto, in the territory of Ancona, translation of the Holy House of Mary, Mother of God, in which the Word was made flesh.
Pope Benedict XIV, a prodigious scholar before he became Pope, established the identity of the house with that of Nazareth, against its detractors, and later worked for the embellishment of the August sanctuary. The feast of Our Lady of Loreto is observed in many provinces of the Church, inscribed in the Proper of their dioceses by their bishops.
Sources: Les Petits Bollandistes: Vies des Saints, by Msgr. Paul Guérin (Bloud et Barral: Paris, 1882), Vol. 14; Magnificatmagazine, Vol. XXIX, no. 12, December 1994, pp. 260-264 (Magnificat: Saint Jovite, 1994); La Sainte Maison de la Sainte Vierge, by a priest of Montreal (Librairie Saint Joseph: Montreal, 1895).
Dom Gueranger also mentions the history of how this feastday became celebrated throughout Italy:
Among the explicit approbations of the holy See regarding the miracle of Loretto, we will mention the Bulls of Paul II, of Leo X, of Paul III, of Paul IV, and of Xystus V; the decree of Urban VIII, in 1632, establishing this feast in the marches of Ancona; the decree of Innocent XII, in 1699, approving the proper Office of the feast; the indults of Benedict XIII, and his successors, extending this feast to several provinces of the Catholic world; and finally, the indult of Benedict XV, extending the office to the whole of Italy.
Collect:
O God, who through the Mystery of the Word made flesh, didst in Thy mercy sanctify the House of Blessed Mary the Virgin, and by wondrous means didst place it in the care of Thy Church, grant that we may keep aloof from the tabernacles of sinners, and become worthy habitants of Thy holy house. Through the same our Lord . . .
Prayer Source: 1962 Roman Catholic Daily Missal
O God, who through the Mystery of the Word made flesh, didst in Thy mercy sanctify the House of Blessed Mary the Virgin, and by wondrous means didst place it in the care of Thy Church, grant that we may keep aloof from the tabernacles of sinners, and become worthy habitants of Thy holy house. Through the same our Lord . . .
Prayer Source: 1962 Roman Catholic Daily Missal