It was not illegal in Christendom. The Catholic schoolmen created a...


The popes recognized that if they were going to go to war, they needed to organize war financing (as explained above), and that called for reversing the most basic teaching of Jesus and his early Christian followers. Rome had to change the Christian opposition to usury because the merchant families who became bankers financing the papacy’s wars insisted on charging it. The Schoolmen, Christian academics, created a scholastic difference between interest and usury. Usury was redefined as “interest” when Christians charged it, at least for purposes blessed by Rome, headed by war loans.”
-Hudson
