It used to be the most important sin of all, condemned by the Torah, the Bible and the Koran, specifically condemned by twelve Church councils as late as 1517. Then, Henry VIII gave us all permission to ignore it by legally redefining usury to mean charging excessive interest over 10%.
There was vicious political debate on the subject up until the 1570s.
What if he had been prevented for some reason? Considering usury was opposed by both Catholics and the emergent Protestants, what impact might such an event have on future trade and economic relationships?
More interestingly, what if the "sin" of lending money at interest was still regarded as one of the worst things you can do?