Paul, the issue is the collapse of Roman imperialism insofar as it opposed and threatened the extinction of the church and the suppression of the gospel - that is, insofar as it could be identified, in Daniel’s symbology, with the beast which made war against the saints of the Most High. I also made the point above that it is a mistake to look with hindsight for exact historical correspondences. Prophetic language doesn’t work in that way. We have to ask how the future looked from the point of view of the New Testament and how they used the Old Testament to construct a narrative of hope for communities facing hostility.

On the second point, my argument is not particularly that the Roman empire collapsed because of the faithful suffering of Jesus and his followers. The enemy of the church collapsed because it came under divine judgment, just as Babylon and Antiochus Epiphanes had done before. In political terms the collapse can be attributed to internal and external causes, but that doesn’t make it any less a matter of divine judgment. But the people of God survived the eschatological crisis by its willingness to endure suffering in the hope of eventual vindication and victory. There are two different issues here.

Having said that, Rodney Stark argues in The Rise of Christianity that the self-sacrificing compassion of Christians during periods of plague was a very significant factor in the Jesus movement became the dominant religious force in the western world, not least because it highlighted the moral bankruptcy of paganism.