Patrick Kiger at National Geographic:
How Money Made Us Modern: About 9,500 years ago in the Mesopotamian region of Sumer, ancient accountants kept track of farmers’ crops and livestock by stacking small pieces of baked clay, almost like the tokens used in board games today. One piece might signify a bushel of grain, while another with a different shape might represent a farm animal or a jar of olive oil.
Those humble little ceramic shapes might not seem have much in common with today’s $100 bill, whose high-tech anti-counterfeiting features include a special security thread designed to turn pink when illuminated by ultraviolet light, let alone with credit-card swipes and online transactions that for many Americans are rapidly taking the place of cash.
But the roots of those modern modes of payment may lie in the Sumerians’ tokens. ...