And the woman which thou sawest - Revelation 17:3.
Is that great city - Represents that great city.
Which reigneth over the kings of the earth - Rome would of course be understood by this language in the time of John, and all the circumstances, as we have seen, combined to show that Rome, in some form of its dominion, is intended. Even the name could hardly have designated it more clearly, and all expositors agree in supposing that Rome, either as pagan or as Christian, is referred to. The chapter shows that its power is limited; and that, although for purposes which he saw to be wise, God allows it to have a wide influence over the nations of the earth, yet, in his own appointed time, the very powers that have sustained it will become its foes, and combine for its overthrow. Europe needs but little further provocation, and the fires of liberty, which have been so long pent up, will break forth, and that storm of indignation which has expelled the Jesuits from all the courts of Europe; which has abolished the Inquisition; which has more than once led hostile armies to the very gates of papal Rome, will again be aroused in a manner which cannot be allayed, and that mighty power, which has controlled so large a part of the nations of Europe for more than a thousand years of the world's history, will come to an end.

And the woman which thou sawest is that great city, which reigneth over the kings of the earth - It has already been shown that the woman sitting upon the seven-headed beast is a representation of the Latin Church; here we have the greatest assurance that it is so, because the woman is called a city, which is a much plainer emblem of a Church, as the word is used unequivocally in this sense in so many parts of Scripture that we cannot well mistake its meaning. See Revelation 3:12; Revelation 11:2; Revelation 21:10; Revelation 22:19; and also Psalm 46:4; Psalm 87:3; Hebrews 12:22, etc. The woman therefore must be the Latin Church; and as the apostle saw her sitting upon the beast, this must signify that ἡ εχουσα βασιλειαν, she hath A Kingdom over the kings of the earth, i.e., over the kings of the Latin world, for that this is the meaning of earth has been shown before in numerous instances. That Kingdom which the woman has over the kings of the Latin world, or secular Latin empire, or in other words The Kingdom of the Latin Church, is the numbered Latin kingdom or Romish hierarchy. See on Revelation 13:18 (note). The woman is also called a Great city, to denote the very great extent of her jurisdiction; for she has comprehended within her walls the subjects of the mighty dominations of France, Spain, England, Scotland, The Empire, Sweden, Denmark, Poland, Hungary, and Portugal. What an extensive city was this! Surely such as to justify the prophetic denomination, that Great city.
Having now gone through the whole of the angel's interpretation of St. John's vision of a whore sitting upon the seven-headed and ten-horned beast, it will be essentially necessary to examine a little more attentively the eighth verse of this chapter. It has already been shown that the phrases, was, is not, shall ascend out of the bottomless pit, and yet is, refer to the Latin kingdom which existed before the building of Rome, to the Roman empire in the time of St. John, and to the Latin empire which was in futurity in the apostolic age. But as the words was, is not, etc., are spoken of the beast upon which the apostle saw the woman, or Latin Church, sit; how can it be said of this beast that it had an existence before the date of the Apocalypse, when the woman whom it carried was not in being till long after this period? And what connection has the Latin empire of the middle ages with that which derived its name from Latinus, king of the Aborigines, and was subjugated by the ancient Romans; or even with that which existed in the time of the apostle? The answer is as follows: St. John saw the beast upon which the woman sat with all his seven heads and ten horns. Consequently, as the angel expressly says that five of these seven heads had already fallen in the time of the vision, it therefore necessarily follows that the apostle must have seen that part of the Latin empire represented by the seven-headed beast which had already been under the emblem of five heads. Therefore the woman sat upon the beast that Was. But it is plain from the angel's interpretation that the whole of the seven heads fell, before the beast upon which the woman sat arose; and yet the woman is represented as sitting upon the seven-headed beast to denote, as we have before observed, that it is the Latin kingdom in its last estate, or under one of its heads restored, which is the secular kingdom of antichrist. The beast is also said not to have any existence in the time of the vision; from which it is evident that the monarchy of the Latins, and not that of the Romans, is here intended; because the latter was in the time of the vision. Again, the beast which St. John saw had not ascended out of the bottomless pit in his time; consequently the whole seven heads and ten horns were in futurity, for all these heads and horns rose up out of the abyss at the same time with the beast. How is this apparent contradiction reconciled? In the most plain and satisfactory manner, by means of the angel's double interpretation of the heads; for if the seven heads be taken in the sense of seven mountains, (head in the Scripture style being a symbol of precedency as well as supremacy), then the beast with all its heads and horns was altogether in futurity in the apostle's time, for the seven heads are the seven electorates of the German empire, and the ten horns the ten monarchies in the interest of the Latin Church. Finally, the beast is said to exist in the time of the vision; therefore the Roman empire, which governed the world, must be here alluded to; and consequently the phrase and yet is is a proof that, as the beast is the Latin kingdom, and this beast is said to have an existence in the time of the apostle, the empire of the Caesars, though generally known by the name of the Roman, is in a very proper sense the Latin kingdom, as the Latin was the language which prevailed in it. Hence the seven-headed and ten-horned beast is at once the representation of the ancient Latin power, of the Roman empire which succeeded it, and of the Latin empire which supports the Latin Church. Here is then the connection of the ancient Latin and Roman powers with that upon which the woman sits. She sits upon the beast that was and is not, because three of his heads represent the three forms of government which the ancient Latins had before they were subjugated by the Romans, viz., the regal power, the dictatorship, and the power of the praetors. She sits upon the beast which Shall Ascend out of the bottomless pit, because all his seven heads, taken in the sense of mountains were in futurity in the apostolic age. She sits upon the beast that yet is, because four of his heads represent four forms of government of the Roman or Latin empire now in existence, viz., the consulate, the triumvirate, the imperial power, and the patriciate. It is hence evident that the beast, in the largest acceptation of this term, is a symbol of the Latin power in general, from its commencement in Latinus to the end of time; his seven heads denoting seven kings or supreme forms of Latin government, during this period, king or kingdom, as we have already observed, being a general term in the prophetical writings for any kind of supreme governor or government, no matter by what particular name such may have been designated among men. Thus the Latin power from the time of Latinus to the death of Numitor was the beast under the dominion of his first head; from the death of Numitor to the destruction of Alba it was the beast under the dominion of his second head; from the destruction of Alba to the final subjugation of the Latins by the Romans the beast under the dominion of his third head. And as the four Roman forms of government which were subsequent to the final conquest of the Latins, were also Latin dominations, the Latin power under these forms of government was the beast under the dominion of his fourth, fifth, sixth and seventh heads. The beast of the bottomless pit, which followed the fall of all the heads of the sea beast or general Latin empire, is, according to the angel's interpretation, ογδοος, (βασιλευς), an Eighth king, i.e., an eighth species of Latin power, or, in other words, a supreme form of Latin government essentially differing from all the foregoing; yet, as it is nominally the same with one of the preceding seven, it is not accounted an eighth head of the beast. The first beast of Revelation 13:1 is a description of the eighth or last condition of the General Latin empire, and is said to arise εκ της θαλασσης, out of the sea, because the heads are there taken in a double sense, sea being a general term to express the origin of every great empire which is raised up by the sword; but when (as in Revelation 17:11) one of the heads of the sea beast (viz., that secular power which is still in being, and has supported the Latin Church for more than a thousand years) is peculiarly styled The Beast, the Holy Ghost, speaking of this secular Latin empire exclusively, declares it to be εκ της αβυσσου, From the bottomless pit.
John Edward Clarke.

And the woman which thou sawest is that (35) great city, which reigneth over the kings of the earth.
(35) That is, Rome that great city, or only city (as Justinian calls it) the king and head of which was then the emperor, but now the pope, since the condition of the beast was changed.

And the woman which thou sawest,.... Revelation 17:3 as there described,
is that great city, often mentioned in this book; great Babylon, the city of Rome, Revelation 11:8 which reigneth over the kings of the earth; which then reigned in John's time over the kings of the earth; and this clearly points out the city of Rome, for there was no other city then, but that, which reigned over the kings of the earth; that was then the metropolis of the Roman empire, to which the whole world was subject; and therefore it is called all the world, Luke 2:1 and since, all the kings of the empire have been under the jurisdiction of Rome Papal. It was formerly called Urbs Regum, a "city of kings" (z), either for the reason in the text, or because its inhabitants looked like kings.
(z) Justin. l. 18. c. 2.

reigneth--literally, "hath kingship over the kings." The harlot cannot be a mere city literally, but is called so in a spiritual sense (Revelation 11:8). Also the beast cannot represent a spiritual power, but a world power. In this verse the harlot is presented before us ripe for judgment. The eighteenth chapter details that judgment.