When coins go out of circulation, after all, the metal doesn’t simply disappear. In the Middle Ages—and this seems to have been true across Eurasia—the vast majority of it ended up in religious establishments, churches, monasteries, and temples, either stockpiled in hoards and treasuries or gilded onto or cast into altars, sanctums, and sacred instruments. Above all, it was shaped into images of gods. As a result, those rulers who did try to put an Axial Age–style coinage system back into circulation—invariably, to fund some project of military expansion—often had to pursue self-consciously anti-religious policies in order to do so. Probably the most notorious was one Harsa, who ruled Kashmir from 1089 to 1101 AD, who is said to have appointed an officer called the “Superintendent for the Destruction of the Gods.” According to later histories, Harsa employed leprous monks to systematically desecrate divine images with urine and excrement, thus neutralizing their power, before dragging them off to be melted down. He is said to have destroyed more than four thousand Buddhist establishments before being betrayed and killed, the last of his dynasty—and his miserable fate was long held out as an example of where the revival of the old ways was likely to lead one in the end.

-- Debt, The First 5,000 Years