The bible speaks of a city...The city is Rome...Home of the Vatican...When the religion of Rome is spoken of, the entire world knows it's the Catholic religion...
The pope is the Bishop of Rome...The vatican has only called itself a city since 1929...
The city is not Rome.
In fact, is it even a city?
Once again, the seven hills of Rome spoken about are on the other side of the Tiber. They do not include the Vatican