It is likely that debt preceded even taxation; but taxes were certainly one of the earliest attributes of organized society. They existed well before coinage. Originally taxes were levied in many different commodities and in labor or services to the rulers

These are two examples of receipts for taxes in barley (NBC5469, NBC5338).

One of the more sophisticated concepts of a developed economy is a rate of interest to be paid for a loan. There is no single universal rate of interest, but a complex set of rates which vary with the length of the loan, the intrinsic risk, legal and other transaction costs, bankruptcy laws, inflation rates, productivity and other factors.

The two tablets in Sumerian and Akkadian include mathematical problems involving interest rates in kind on barley at 33 1/3% and on silver at 20% (YBC4698, YBC4669). The Babylonians understood the critical productive role of a rate of interest which Aristotle could not grasp and which was profoundly misunderstood in both Catholic and Moslem theology.