The Florentines became the banking center of europe. They would give money to a noble family in exchange for Letting the merchant use their land force. Loaning money was still very dangerous. There was no way to ensure you'd get it back. One could just say i'm not gonna pay you back. I'll kill you instead Yeah So what happened is that as economic activity expanded the papacy started to change its opinions and become to insist that interest needed to be paid on risky investments.