THE BEAST AND THE GREAT HARLOT
“So he carried me away in the Spirit into the wilderness. And I saw a woman sitting on a scarlet colored beast, full of names of blasphemy, having ten heads and ten horns. And the woman was arrayed in purple and scarlet, and adorned with gold and precious stones and pearls, having a golden cup in her hand full of abominations and filthiness of her fornication. And on her forehead a name was written, MYSTERY, BABYLON THE GREAT, THE MOTHER OF HARLOTS AND OF THE ABOMINATIONS OF THE EARTH ” (Revelation 17:3-5).
In 12:1,2 The Woman we saw that a woman represents the people of God (Israel in the Old Testament, the church in the New Testament), either pure and faithful, or apostate and corrupt. In this case the woman is called “the great harlot,” indicating that this is a corrupt, apostate church. Here we see a great political entity (the "scarlet beast") which is being ridden, or controlled, by a corrupt church ("the great harlot"). Verse five gives the names of this church—“MYSTERY, BABYLON THE GREAT, MOTHER OF HARLOTS AND OF THE ABOMINATIONS OF THE EARTH.” Each of these names describes an aspect of the papal Roman Catholic Church.
“Mystery” is an appropriate title for the Roman Church because it considers its sacraments to be mysteries, especially the Eucharist, which is the central act of Catholic worship. “The church honors the Eucharist as one of her most exalted mysteries, since for sublimity and incomprehensibility it yields in nothing to the allied mysteries of the Trinity and Incarnation. These three mysteries constitute a wonderful triad, which causes the essential characteristic of Christianity, as a religion of mysteries far transcending the capabilities of reason, to shine forth in all its brilliance and splendor, and elevates Catholicism, the most faithful guardian and keeper of our Christian heritage, far above all pagan and non-Christian religions”.
The title “Babylon” is also appropriate for the Roman Church. The apostle Peter identified Rome as Babylon (1 Peter 5:13), and chapter 18, which deals with the judgment of Babylon will show clearly that the characteristics of the Catholic Church are those of Babylon.
She is also called the “Mother of Harlots.” The Roman Catholic Church calls herself the “Mother Church.” The Tridentine creed of Pope Pius IX, drawn up after the watershed Council of Trent states, “I acknowledge the Holy Catholic Apostolic Roman Church for the mother and mistress of all churches.” In his Encyclical on Religious Unity of 1928 Pope Pius XI appealed to the various “reformers,” “Let them therefore return to their common Father, who, forgetting the insults previously heaped on the Apostolic See, will receive them in the most loving fashion. For if, as they continually state, they long to be united with Us and ours, why do they not hasten to enter the church, the Mother and mistress of all Christ’s faithful?”
This woman “committed fornication” (had illicit relationships) with “the kings of the earth” (v. 2), which indicates a union of church and state. This, of course, has been the policy of the Catholic Church ever since the time of Constantine. In time the church became so powerful that her law was the law of the land. This allowed her to carry out "the abominations of the earth"—the persecution and extermination of the “heretics” who refused to accept her dogmas.
The false doctrines that led to the abuses of the Middle Ages will be examined in 18: 1-3 Babylon is Fallen. Although the Roman Catholic Church has expressed regret for some of her actions during that horrendous period and no longer practices them, none of the doctrines that led to those abuses have changed. This is not to say that Catholics are pagans or wicked people. According to Revelation 18:1-4, many of God’s people are found in Babylon, serving Him sincerely according to their understanding of His will as it has been taught to them. However, the papal system was used by Satan to persecute God’s people during the Middle Ages, and although it is apparently benign now, this chapter teaches us that it will be integrally involved in the future Babylon that will take the lead in persecuting God’s people during the time of trouble.
 http://catholictradition.org/Tradition/tridentine-creed.htm Accessed Sept. 16, 2014
 “The official recognition of Christianity [by the state] had some unfortunate effects on the church. For the first time, the church attracted many people who lacked the dedication of the early Christians. Emperors intruded into the internal affairs of the church…But on the whole, the empire’s recognition of Christianity benefited the church. The Church was able to influence civil laws.” "Roman Catholic Church" World Book Encyclopedia (Chicago, IL 1986).