The disasters that are heralded by the first four "trumpets" of the Great Tribulation (Revelation 8:6-12) are mentioned in this chapter. It is interesting that the word "chernobyl" is the Russian name for the poisonous "wormwood" plant. The passage from Revelation 8 says that the asteroid that hits the earth will be called "Wormwood".
This chapter also reveals a little more of the powers that the Two Witnesses will be able to wield. Read about them in Revelation 11:6.
The main lesson, however, is that of leadership. The beastly systems of the world all jostle for power, wealth, fame, and honour. But the humble, sacrificial death of the "Lamb" is what characterises the kingdom of heaven.
What a shame that Constantine did not have the opportunity to learn as Fitzhugh does in this chapter, what it means to be a true leader in the kingdom of heaven! Only when that happens will people understand that it would be better for the leaders of the most powerful countries and empires in history to be humble missionaries and servants in the kingdom of heaven than to supposedly "use their power" to bring favours for God and for his people.
Pius represents the tragic end that befalls those who refuse to leave their positions of power along with everything else that God calls us to forsake in order to enter his kingdom.