In a post titled, There was something awful about the 20th century, Monsignor Pope mentions the Prayer to St. Michael, which Leo XIII ordered to be said after all low Masses, a practice in use until the reforms of Vatican II. The vision of Pope Leo might be apocryphal, but the insertion of the prayer at the end of Mass is not. Monsignor records the vision as follows:
October 13, 1884, Pope Leo XIII had just finished celebrating Mass in a chapel in the Vatican. At the Mass were a few Cardinals and members of the household staff. Suddenly the Pope stopped at the foot of the altar. He stood there for about 10 minutes, as if in a trance, his face ashen white. The going straightway from the Chapel to his office, he composed the prayer to St. Michael and later issued instructions that it be said after all Low Masses everywhere in the world. He explained that, as he was about to leave the foot of the altar, he had suddenly heard voices – two voices, one kind and gentle, the other guttural and harsh. There he heard the voice of Satan in his pride, boasting to Our Lord: “I can destroy your Church.” The gentle voice of Our Lord: “You can? Then go ahead and do so.” Satan replied, “To do so, I need more time and more power.” The Lord said, “How much time? How much power?” “75 to 100 years, and a greater power over those who will give themselves over to my service.” was Satan’s reply. Mysteriously our Lord said, “You have the time, you have the power. Do with them what you will.” - SourceI've always accepted the story of the vision as true, but apparently there is no official documentation of it. When I was little, it was my understanding the St. Michael prayer was said for the conversion of Russia.
I was thinking of the vision all day however, and I couldn't help wonder about all the subsequent prophecies of a great chastisement for the sins of the world - if indeed Satan had been given permission to destroy the Church and lead souls to perdition, why should we be chastised? The devil started it. Then I remembered the test in the Garden of Eden... the story of the prophet Job... the temptation and Passion of Our Lord Jesus Christ.
Saint Michael the Archangel, defend us in battle, be our protection against the malice and snares of the devil. May God rebuke him we humbly pray; and do thou, O Prince of the Heavenly host, by the power of God, thrust into hell Satan and all evil spirits who wander through the world for the ruin of souls. Amen.Lord Jesus Christ, Son of God, have mercy on me a sinner.
Oh - as for the hundred years time limit - I think we are overdo for a correction - but remember, God measures time differently than we do.