But the dragon symbolized Rome, and why not let that symbol continue to represent it?
Whoever attempts to answer this question must say that it is because a change had taken place in the power.

What change?
Two kinds of changes are conspicuous in the history of Rome: changes in form of government, and a change in religion.

But this cannot denote any change in the form of government; for the seven different forms of government that Rome consecutively assumed are represented by the seven heads of the dragon, and the seven heads of the leopard beast.

The religious change must therefore be alone denoted by this change of symbols.

Paganism and Christianity coalesced, and the mongrel production was the papacy; and this new religion, and this alone, made a change in the symbol necessary.