Domitius Aldori-Solanus:
So how much interest is the bank paying on the money left with them?
I don't think you quite understand the principles of medieval banking, yet. The bank will keep your money safe. That is what you pay a fee for, and you only pay it on withdrawal because that is when you actually have proof that the bank has performed that service for you. Look on the bright side - the bank's fee doesn't increase over time, regardless how long you want the bank to keep your money safe for you. If you never withdraw your money from the bank, you won't ever have to pay a fee! :o)