your opinions are actually backwards.
Rome persecuted the Bible and the believers. The Bible was an illegal book to own. Why do you suppose that was? Because the Bible condemns the Roman Babylonian worship system. Rome has never promoted the Bible. But rather just the opposite.
They did eventually make it legal to be a Christian, only to try and gain more power over the people.
Why do you think Rome switched from Casar's to Popes? Because a Pope is world wide, and Casar is only nation wide.
Think about it