Christians and Muslims who could not agree on religious beliefs
could nevertheless agree on a monetary belief, because
whereas religion asks us to believe in something, money
asks us to believe that other people believe in something.
The Indians had such a strong confidence in the denarius and the image of the emperor that when local rulers struck coins of their own they closely imitated the denarius, down to the portrait of the Roman emperor! The name 'denarius' became a generic name for coins. Muslim caliphs Arabicised this name and issued 'dinars'. The dinar.