I am a Catholic, and many of Catholic prophecy's of old talk of this. I never saw how it could happen until the days we are living in.
It is important to understand that “Rome” they speak of is actually its own state. That means the Vatican can and will act on its own accord. It doesn't need Italy to approve, condone, etc.
The Swiss Guard is not only ceremonial, but they are real working soldiers or even mercenaries.
“Rome” will not go down without a battle.