Collecting ancient coins is fun because each coin is a time machine. You hold it in your hand and find yourself transported back to the time when it was struck. Since we're on the subject of Christianity and Rome, let us examine a numismatic link between them.
The coin shown below is a part of my ancient coin collection.
Known as an AE Prutah, this is the ancient Roman bronze coin of Jerusalem. Prutah is a word borrowed from the Mishnah and the Talmund meaning "a coin of smaller value" -- one thousandth of a pound. A loaf of bread at that time sold for 10 Prutot (plural form). Prutot were manufactured in Israel because the Jewish people refused to trade in Roman coinage.