The financial contract called the pruzbul was instituted by Hillel. Hillel (2030 years ago) saw that sometimes people wouldn't want to lend money, due to the cancellation of debts by the Shemitta year (seventh year) (Deuteronomy, ch. 15), after which the lender would have to forgo collecting the money that had been owed to him. Hillel decided that it would be preferable to create a way of collecting debts without violating the Shemitta cancellation, so that people would be willing to lend money. The Pruzbul is a form of contract that makes that possible.