Revelation 17:9: And here is the mind which hath wisdom. The seven heads are seven mountains, on which the woman sitteth.

The angel from Revelation 17:1¹ continued to explain to John the mystery of the beast, who is also the Great Whore,² with an exhortation,³ saying: here is the mind which hath wisdom. This means that minds with wisdom can interpret the symbolism of the beast and the Great Whore.⁴ However, the wise must take the Holy Spirit for their guide.⁵ Revelation 13:18 contains a similar admonition, saying: "Here is wisdom. Let him that hath understanding count the number of the beast." That number and name is 666.⁶ The admonitions are virtually the same because they both apply to the latter days where the Great Whore and the Second Beast named 666 are both parts of the same Modern Babylon.

In this verse the angel explains to John the seven heads that correspond to the First Beast from Revelation 13:1, which evolves into the Second Beast in Revelation 13:11.⁷ The seven heads represent an earthly kingdom that derived its power from Satan.⁸ The angel explains further that the seven heads are seven mountains, on which the woman sitteth.⁹ Most scholars agree that this imagery represents the ancient city of Rome¹⁰ that was built upon seven hills.¹¹ At the time of Christ, Rome was the seat of world power on the Mediterranean Sea.¹² This may partially explain why John saw the image of a seven-headed First Beast rise up out of the sea in Revelation 13:1.¹³

The seven hills of Rome are called mountains to emphasize the vast power that Rome exercised against the saints of God anciently.¹⁴ John borrows this familiar symbol for Rome and then adds the symbolic image of a woman that sits on, and is therefore supported by, the seven mountains of Rome. Taken together, these symbols represent the false religion of Rome as of 70 AD.¹⁵ Rome's complete power and dominion on the seven hills continued until the end of the Holy Roman Empire in 1806.¹⁶ By that time, the influence of the woman sitting on seven mountains had grown beyond the ancient boundaries of the Roman Empire until she had become the great whore that sitteth upon many waters in all the world.¹⁷

The seven symbolic heads of the Beast also have a dual meaning. The seven heads relate to the seven mountains of ancient Rome and also to the seven kings that represent seven worldly empires,¹⁸ which the angel explains in Revelation 17:10.¹⁹