Revelation 17: 6b-18
The angel goes on to explain that the beast’s seven heads are seven mountains or kings, both an expression for kingdoms (nations) or empires. In other words, the beast throughout history has acted through its successive heads. These heads/ mountains/kings are seven dominant, successive world powers that Satan has worked through to oppress God’s people. John says that five have fallen, one is, and another has not yet come.
From John’s perspective, the five have fallen kingdoms would have ruled the world before his time. They are Egypt, Assyria, Babylon, Persia, and Greece; all oppressors of God’s people. The one is empire would be pagan Rome because it was current during John’s time. The another has not yet come, again from John’s perspective, turns out to be papal Rome.
The angel further explains to John that also there is an eighth [kingdom] and is one of the seven. It’s called an eighth head, but only in the sense of distinguishing it from the seven heads. This eighth kingdom is the beast itself, fully restored. Yet it is one of the seven kingdoms, because like them, it too is a ruling oppressive power. In fact, it can be thought of as the summary or conclusion of the seven.
The angel says that this eighth kingdom is the beast which was and is not. That means that it lived (was), died (is not), but as can be seen, is now resurrected. Therefore, the eighth kingdom is the seventh head that lived, was wounded to death, but is now fully healed. The eighth kingdom comes into being, when after a couple of centuries of not being able to persecute God’s people, it will fully regain the power to do so at the end of the age. But those circumstances will only remain for a little while because of Jesus’ return.
Right now, we are living in the era of the seventh head. The eighth, with its ten united and supportive ten kingdoms, has not yet ascended from the abyss.
Speaking of the ten kingdoms, they are represented by the ten horns of the beast. These ten kingdoms, yet to appear on the scene, are not identified. I go along with those who think “ten,” in this case, is a round number that refers to the totality of all the nation powers in the world, whatever the actual number may turn out to be. The kingdom that they will receive will be comprised as a world-wide confederacy of nations putting themselves in the service of the beast. These nations will receive authority as kings over the world together with the beast for a short period of time.
These nations will unite the minds of the world to join the battle against Christ and His people, the climax of which is described in Rev. 19: 11-21. At the point of the nations final assault against God’s called, elect, and faithful, Christ intervenes. At the brightness of His coming, He overcomes the world-wide confederacy, the beast, and the false prophet.