We don’t know precisely when and how interest-bearing loans originated, since they appear to predate writing. Most likely, Temple administrators invented the idea as a way of financing the caravan trade. This trade was crucial because while the river valley of ancient Mesopotamia was extraordinarily fertile and produced huge surpluses of grain and other foodstuffs, and supported enormous numbers of livestock, which in turn supported a vast wool and leather industry, it was almost completely lacking in anything else.
