Alphonse Ratisbonne was born a Jew in the Alsace region of Eastern France and would, over the years, develop a particular disdain for the Catholic Faith. Fully embracing the wave of new philosophic trends and scientific advancements, he looked upon Catholics as naive, superstitious, unintelligent and foolish.
This prejudice would grow to outright hatred when his older brother converted to Catholicism and became a Jesuit priest, essentially "betraying" his family and heritage.
In 1842, on a journey for pleasure undertaken before he was to marry, Ratisbonne made the decision to take a slight detour and pay a visit to Rome. It was there he met a priest, a brother of an acquaintance, who would dedicate himself to the cause of this unlikely candidate's conversion. In an effort to demonstrate the frivolity of Catholicism, Ratisbonne agreed to wear a Miraculous Medal and recite the Memorare daily. Additionally, for his own entertainment and prideful appetite, Ratisbonne would accompany his new acquaintance around Rome, never missing an opportunity to ridicule and blaspheme all he would hear and see.
Our Lady of the Miracle
All that would change on January 20th, when he visited the Church of Sant' Andrea delle Fratte. It was within the walls of this historic church where Ratisbonne would be instantaneously converted by the Mother of God Herself.
“At the moment when the Blessed Virgin made a sign with her hand, the veil fell from my eyes; not one veil only, but all the veils that were wrapped around me disappeared, just as snow melts beneath the rays of the sun.” 
The Mother of God would present to him the glories of the Faith and instantly educate him in its sacred truths.
“It is well known that I never opened a religious book and had never read a page of the Bible, and that the dogma of Original Sin, which it is either denied or forgotten by modern Jews, had never for a single moment occupied my thoughts—indeed, I doubt I had ever heard its name. How did I arrive at a knowledge of it? I know not. All I know is that when I entered that church I was profoundly ignorant of everything, and that when I came out I saw everything clearly and distinctly.” 
In another, he said: “I was scarcely in the church when a total confusion came over me. When I looked up, it seemed to me that the entire church had been swallowed up in shadow, except one chapel. It was as though all the light was concentrated in that single place. I looked over towards this chapel whence so much light shone, and above the altar was a living figure, tall, majestic, beautiful and full of mercy. It was the most holy Virgin Mary, resembling her figure on the Miraculous Medal. At this sight I fell on my knees right where I stood. Unable to look up because of the blinding light, I fixed my glance on her hands, and in them I could read the expression of mercy and pardon. In the presence of the Most Blessed Virgin, even though she did not speak a word to me, I understood the frightful situation I was in, my sins and the beauty of the Catholic Faith.”
After a thorough inquiry and investigation, Pope Gregory XVI declared the event a true miracle. There was no natural explanation to what happened on that particular day. As Ratisbonne's Roman companion recounts:
“Even if we imagine an illusion in the case of a person of Ratisbonne's character and education, with prejudices so violent, and with such interest both of affection and of position, it could not have been induced or augmented by any outward representation; for in the chapel that was the scene of the miracle, there is no statue, or picture, or image of the Blessed Virgin of any kind.” 
Alphonse Ratisbonne was baptized, ordained and joined the very Society of Jesus he had so violently despised. As he predicted, his family disowned him and revoked his partnership in the bank which was to be his inheritance. He would later receive permission to leave the Jesuits to start the Sisterhood of Our Lady of Sion, which dedicated itself to the conversion of Jews. The sisterhood soon moved to Jerusalem where it established two convents, two schools, three orphanages and a church. The priests assisting Ratisbonne, known as the Peres de Notre Dame de Sion later returned to Europe to establish additional foundations. Less than a century later, during the Nazi persecutions, these holy priests were among the most active rescuers of Jews. 
As was the case when She appeared to St. Juan Diego three centuries earlier, Our Lady demonstrated the same “simplistic” outlook towards Catholicism and conversion that many Catholics today are mocked for maintaining. She did not fill Ratisbonne with a newfound respect for Judaism or encourage him to follow his conscience and “be the best Jew he could be” [indirectly promoting Indifferentism and Pluralism]. She clearly showed him the error of his ways and the true light of the Catholic Faith. She did not enlighten him as to the permanence of the Old Covenant, suggest that conversion may not be necessary for his eternal salvation or apologize for past actions of Catholics [although an apology for Her presumptuous actions that day may be in the works]. Following Our Blessed Mother's heavenly example, Ratisbonne would take this holy gift and make it his mission to provide it to as many other Jews as possible.
The story of Ratisbonne's conversion is not ancient history. This wasn't a Roman centurion or even a medieval prince; he was a modern man in every sense of the term. He was well-educated in the ways of science and modern philosophy, had a prestigious position as a wealthy banker, was betrothed to a beautiful young girl and had every reason in the world to remain in his current state of worldly pleasures. The unlikelihood of the miraculous occurrence was not lost of the recent convert:
“O my God. . . . I who only a half hour before was still blaspheming! I who felt such a deadly hatred of the Catholic religion! And all who know me well enough that, humanly speaking, I have the strongest reasons for remaining a Jew. My family is Jewish; my bride is Jewish; my uncle is a Jew. In becoming a Catholic, I sacrifice all the interests and all the hopes I have on earth; and yet I am not mad. Everyone knows that I am not mad, that I have never been mad. Surely they must receive my testimony . . .”
“A man has a claim to be believed, when he sacrifices everything to a conviction that must have come from Heaven. If all that I have said is not rigorously true, I commit a crime, not only the most daring, but the most senseless and motiveless.” 
Men in Alphonse Ratisbonne's pre-conversion condition are anything but a rarity; millions could easily be found today. However, the nature of priest the Blessed Virgin called him to become is becoming increasingly scarce. Her clear example provided by the conversion of this "modern man" has fallen into the dustbin of history...
1 "The Conversion of Ratisbonne" Roman Catholic Books, p.71 (2000)
2 Ibid., p.71
3 Ibid., p.37
4 Ibid., p.75
2 Ibid., p.71
3 Ibid., p.37
4 Ibid., p.75
1. “From Ratisbonne to Reflections” by Peter W. Miller