Credit came before currency. The oldest civilizations we know of (Sumerians, Babylonians, etc.) traded on credit on the daily to be later settled come harvest.

Credit came before currency. The oldest civilizations we know of (Sumerians, Babylonians, etc.) traded on credit on the daily to be later settled come harvest. "Okay, I owe the bar for 100 barley beers, it's harvest time and they have to pay their taxes too. I'll pay 100 barley beers in grain to the taxman in their name when I go pay mine."