Thank you for your question.
Revelation 17:7 And the angel said unto me, Wherefore didst thou marvel? I will tell thee the mystery of the woman, and of the beast that carrieth her, which hath the seven heads and ten horns. 8 The beast that thou sawest was, and is not; and shall ascend out of the bottomless pit, and go into perdition: and they that dwell on the earth shall wonder, whose names were not written in the book of life from the foundation of the world, when they behold the beast that was, and is not, and yet is. 9 And here is the mind which hath wisdom. The seven heads are seven mountains, on which the woman sitteth. 10 And there are seven kings: five are fallen, and one is, and the other is not yet come; and when he cometh, he must continue a short space. 11 And the beast that was, and is not, even he is the eighth, and is of the seven, and goeth into perdition. 12 And the ten horns which thou sawest are ten kings, which have received no kingdom as yet; but receive power as kings one hour with the beast. 13 These have one mind, and shall give their power and strength unto the beast. 14 These shall make war with the Lamb, and the Lamb shall overcome them: for he is Lord of lords, and King of kings: and they that are with him are called, and chosen, and faithful. 15 And he saith unto me, The waters which thou sawest, where the whore sitteth, are peoples, and multitudes, and nations, and tongues. 16 And the ten horns which thou sawest upon the beast, these shall hate the whore, and shall make her desolate and naked, and shall eat her flesh, and burn her with fire. 17 For God hath put in their hearts to fulfil his will, and to agree, and give their kingdom unto the beast, until the words of God shall be fulfilled. 18 And the woman which thou sawest is that great city, which reigneth over the kings of the earth.
The ‘Beast’ is a composite of the nations/empires that oppressed Israel culminating in Rome. The seven heads are consecutive; the head in John’s day was the sixth – Rome. The ‘Harlot’ did not ride the beast until the time that the seventh head – Constantinople - came into being. The ‘Harlot’ is the Christian Church which by the beginning of the fourth century had become corrupt and adopted false doctrine and by the end of the fourth century became the State Church of the Empire.
It began the fourth century as a persecuted church and ended it as a persecuting church. From this position it made its ascent to rule over kings. The Church ruled the lives of men and women throughout the civilised world. This is symbolised by the woman sitting upon ‘many waters’ which are said to be ‘peoples, and multitudes, and nations, and tongues (languages)’.
The Pope in Rome became its Western head and during what is known as the Dark Ages it struggled for supremacy via the Holy Roman Empire with the kings of the earth. Pope Innocent III, 1198 "The Creator set up two great lights in the heavens; the greater light to rule the day, the lesser light to rule the night. In the same way, the Church has set up two great lights on earth; the greater light, being the Pope, to rule over souls; the lesser light, being the king, to rule over bodies. Just as the moon’s light comes from the sun, does the power of the king come from the Pope. The more closely a king is willing to follow the Pope’s rule, the greater his light will be.” This is symbolised in v18 ‘the woman... is that great city, which reigneth over the kings of the earth. The Church’s policy of extermination of ‘heretics’ made it ‘drunken with the blood of the saints, and with the blood of the martyrs of Jesus’ (v6). The fall of Constantinople (the seventh head) in 1453 was followed by the Reformation.
The Reformation saw the dissemination of the printed Bible which the Church failed to suppress and with it the rise of Protestant Churches.
The Protestant Churches kept the false doctrines and in so doing became daughters of the Mother Church, which is how the ‘Mother’ Church sees them. At the same time the independent kingdoms which arose from the old Roman Empire cast off the Church yoke, destroyed monasteries and confiscated Church wealth. English history records the struggle of Henry VIII with Rome and the aftermath. This is what is symbolised by the ten horns stripping the ‘Harlot’ naked and burning her with fire.
The French revolution broke the Church hold on France. The Holy Roman Empire came to an end in 1806. In 1809 Napoleon deprived the Papacy of temporal power and the Popes became virtual prisoners in the Vatican from 1870 until 1929 when the Vatican State was again given political independence. The ‘Harlot’ will not again ride the ‘Beast’.
At the time of the end the Church holds the position of the ‘False Prophet’. The ten kingdoms which currently form part of those struggling to form the European Union are destined to voluntarily hand over their government to the ‘Beast’ resurrected in the form of the eighth head. On this basis it seems unlikely that the present EU will ever agree a ‘Constitution’. In my opinion the eighth head is Russia, which makes the Beast correspond with ‘Gog of the land of Magog’ in Ezekiel 38. I expect Europe to turn from support of the USA towards Russia and find the unity that the European nations seek under the Russian umbrella.
At the same time I expect the Eastern and Western Churches to come together and apostate Christianity to be adopted as the ‘False Prophet’ (Revelation 16:13).
The northern invasion of Israel in the last days brings the ‘ten kings’ and the ‘Beast’ into conflict with the ‘Lamb’ at Armageddon.
The fall of the Vatican state is described in Revelation 18:2 ‘Babylon the great is fallen, is fallen...’
I hope this helps.