The Christian Church regularly prohibited usury (the credit transaction), which it considered a sin. Of course, no matter how much you prohibit credit, it will always exist—it’s inherent in human nature. However, the form of credit matters. Banks and their clients soon found a way to “legally” circumvent the Church’s prohibition. The client gave money to the bank, but formalized the transaction as a storage agreement—a deposit. At some point, the client supposedly came for his money, which the banker did not have. The banker paid a penalty to the client, provided for by the deposit agreement, but in reality this was interest on the loan. This continued throughout the entire term of the transaction, to everyone’s satisfaction.
It is funny that the Church has long since stopped prohibiting interest on loans (and even if it did, no one would pay attention anymore), but the cunning procedure that arose during this time is regularly reproduced. Why? This maneuver, in essence, legalizes the fact that banks appropriate part of the deposits to issue them as loans to third parties. This legal trick allowed mixing together completely different transactions from both a legal and economic point of view—deposits and loans.