[rmc]

Fun fact: Charging interest used to be against Christian principles aswell. Instead people would borrow from Jews (who did charge interest). The Magna Carta (in England) has sections on what exactly happens if someone ones money to Jews and dies (for example).

[jdotjdot]

That's why usury was traditionally a Jewish profession in the Middle Ages--they were the only ones allowed to do it (and sometimes it was the only thing they were allowed to do).