 A cornerstone of monetary theory, and arguably the most robust and enduring law in economics, is the quantity theory of money that commits to a causal and positive function between the price level and the money supply, treating the latter as the independent variable, that is, \(P = f(M^s)\) (see Schabas &amp; Wennerlind 2020: 151–172). With the influx of silver from Latin America after Columbus, the money supply in Europe had more than doubled by 1510. While entering exclusively on Spanish ships, it spread rapidly, first to the Netherlands and then across Europe. Prices rose as well, although the underlying factors were not readily understood. Most purchases were of food, whose prices fluctuated with the harvests, good and bad. Consumer durables tended to be purchased infrequently, often at seasonal fairs, which had complex systems for price negotiations, pitching and haggling. The rise of middlemen, wholesale markets and retailing, became more prevalent in the seventeenth century, although the public was suspicious that these traders who lived well off their earnings were the cause of increasing prices. Although newspapers and broadsides posted prices, starting in the late seventeenth century, urban shopping still required negotiation. It was only with the department stores of the late nineteenth century that prices were routinely posted.