Reformers taught the beast of Revelation was Catholism and it sparked the Protestant Reformation.

Revelation 17

For eleven hundred years, Christians have identified the Church of Rome as being the Whore of Revelation 17.

By 900 A.D., "Tergandus, Bishop of Treves, called the Pope antichrist, yea, a wolf, and Rome, Babylon" (Martyrs Mirror, 5th English edition, p. 240).

In the tenth century, Arnulphus, Bishop of Orleans, called the Pope Antichrist, in a full council at Rheims (Peter Allix, The Ecclesiastical History of the Ancient Churches of Piedmont, 1821, p. 229).

The Waldensian treatise titled the Noble Lesson, dated 1100 A.D., stated: "Antichrist, the predicted murderer of the Saints, hath already appeared in his true character, seated monarchally in the seven-hilled city." In 1120 or 1160 A.D., A Treatise Concerning Antichrist identified the Pope of Rome as the Antichrist. George Faber identifies this as a production of Peter the Valdo (Faber, pp. 379-384).

In 1206, the Albigenses made the following confession: "That the Church of Rome was not the spouse of Christ, but the Church of confusion, drunk with the blood of the martyrs. That the polity of the Church of Rome was neither good nor holy, nor established by Jesus Christ" (Peter Allix, The Ecclesiastical History of the Ancient Churches of the Albigenses, 1821 edition, first published in 1692, p. 178).

Throughout the Reformation era, Rome was considered the Mother of Harlots. On September 9, 1560, Pastor Jean Louis Paschale of Calabria, just before he was burned alive in the presence of Pope Pius IV in Rome, turned to the Pope and "arraigned him as the enemy of Christ, the persecutor of his people, and the Anti-Christ of Scripture, and concluded by summoning him and all his cardinals to answer for their cruelties and murders before the throne of the Lamb" (J.A. Wylie, History of the Waldenses, c1860, p. 120).

William Tyndale identified the Pope as Antichrist in his treatise "The Practice of Prelates" and in his Preface to the 1534 edition of the New Testament. Many of the early Protestant Bibles contained artwork that portrays the Scarlet Woman of Revelation 17, and identifies the Roman Catholic Church as this apostate religion. In his 1893 work titled Union with Rome, Bishop Christopher Wordsworth of the Church of England stated the view which prevailed among Protestants at that time: "... we tremble at the sight, while we read the inscription, emblazoned in large letters, `Mystery, Babylon the Great,' written by the hand of St. John, guided by the Holy Spirit of God, on the forehead of the Church of Rome."

John Wesley's Notes; But he that had the mark, namely, the name of the first beast, or the number of his name - The name of the beast is that which he bears through his whole duration; namely, that of Papa or Pope: the number of his name is the whole time during which he bears this name. Whosoever, therefore, receives the mark of the beast does as much as if he said expressly, "I acknowledge the present Papacy, as proceeding from God;" or, "I acknowledge that what St. Gregory VII. has done, according to his legend, (authorized by Benedict XIII.,) and what has been maintained in virtue thereof, by his successors to this day, is from God." By the former, a man hath the name of the beast as a mark; by the latter, the number of his name. In a word, to have the name of the beast is, to acknowledge His papal Holiness; to have the number of his name is, to acknowledge the papal succession. The second beast will enforce the receiving this mark under the severest penalties. (John Wesley, Explanatory Notes on the Whole Bible, Revelation 13:17)

There are hundreds of thousands of Protestant Christians who identify Rome as the Whore of Revelation 17. The Roman Catholic Church partially fulfills the prophecy in Revelation 17 of a one-world religious Whore. But Revelation 17 is not entirely fulfilled by Roman Catholicism. This prophecy will not be complete until the reign of the Antichrist just prior to the coming of the Lord, and Rome will be joined by a coalition of other apostate Protestant churches. This is the objective of the present Ecumenical Movement. Every feature of this religious Whore is fulfilled by the Roman Catholic Church: Being united with secular government, clothed in purple and scarlet, having great wealth, found in every nation, kindred, tongue and people, drunk with the blood of the saints.

If all these testimonies of the past one thousand years provided sufficient evidence to identify the Roman Church as this Great Whore, then all remaining elements of the prophecy must also match. Of those that have already passed, they all match. Of those elements that are yet to happen, they will also match.

Rome has not ignored this notoriety, but has engaged in a campaign of dissuading the public opinion away from being identified as the Whore and the Beast of Revelation 17. Many books and web sites today have much to say about the antichrist and the number 666, and in them, you will not find one reference to Rome, Catholicism, or the Papacy. The Ecumenical Movement has thus been a successful endeavor of the Papists.

During the Reformation, when scripture was exploding off the Protestant printing presses in the common tongue, instead of Latin, it became apparent to students of Bible prophecy that the Antichrist beast and apostate Mystery Babylon of the books of Daniel and Revelation was already on the scene, and had been for over a thousand years! Because of their Bible study, John Wycliff, John Hus, William Tyndale, Martin Luther, Philipp Melanchthon, John Calvin, John Knox, Huldreich Zwingli, and John Wesley all identified the Papacy of the Roman Catholic Church as the Antichrist power and apostate Mystery Babylon, as did many others. If the giants of the Reformation came to this conclusion, some even being burned at the stake for their belief, then when and how did Protestantism abandon the Historicist interpretation and adopt Futurism, where the Antichrist is some unknown unidentified figure off in the future?

Briefly, both Preterism and Futurism were concocted by Jesuit priests during the Reformation in order to take the heat off of the Catholic Church and counter the Historicist interpretation put forth by the heretical Protestants. Particularly in the last 100 years or so, the Catholic Futurist interpretation has gradually taken hold in Protestantism, and one of its main proponents for the last 20 years or so has been Hal Lindsey, who has appeared frequently on TBN, which airs his weekly prophecy program.