What then must [the] symbol, the Babylonian harlot represent? Surely some false and apostate church, some church which, while professing to belong to Christ, is in reality given up to fellowship with the world, and linked in closest union, with the kings of the earth; a worldly church, which has left her first love, forgotten her heavenly calling, sunk into carnality and sin, and proved shamelessly and glaringly faithless to her Lord.
The last words of the angel to John, seem to leave no possibility of mistake as to the city. "The seven heads are seven mountains on which the woman sitteth . . . and the woman which thou sawest is that great city which reigneth over the kings of the earth." What city was that? There was but one great city, which in John's day reigned aver the kings of the earth. It was ROME; and Rome is the only city which was great then, has been great, in one way or other, ever since, and is so still. And Rome was seated on seven hills, "the seven mountains on which the woman sitteth." Her common name with the classic writers of St. John's age, is "the seven hilled city ;" an annual festival used to be held in honour of the "seven hilled city;" every Latin poet of note during a period of five hundred years, alludes to Rome's seven hills; their names were the Palatine, the Quirinal, the Aventine, the Caelian, the Viminal, the Esquiline, and the Janiculum hills. The medals and coins of the day, represent Rome as a woman sitting on seven hills; and her titles show with sufficient clearness, how thoroughly she reigned. She was styled "the royal Rome " "the mistress of the world ;" "the queen of nations. Her sway was all but universal. She was the metropolis of that fourth great empire which Daniel had foretold would break in pieces and subdue all things, "dreadful and terrible and strong exceedingly;" and at the time of the Apocalyptic visions, her power was at its height. Rome, and no other city can be intended here; the woman is in some way identified with Rome. We previously saw that she must represent a church, now we know what church. The harlot is the Church of Rome; for simple minds there seems no escape from this conclusion. And it is a singular and notable fact, that no other city but Rome, has ever given its name to a church, which has embraced many kindreds and nations. Many countries have done so, and even individuals; but as far as we are aware, no other city.
--H. Grattan Guinness (The Approaching End of the Age, part 3, chapter 1)