The history of ancient coinage provides a case study in how economic institutions, once established, develop their own logic that can override the intentions of their creators and create structural problems that prove very difficult to solve.

The Roman denarius, introduced in 211 BC during the stress of the Second Punic War, was established as a silver coin of high purity (nearly pure silver). For four centuries it served as the backbone of the Roman monetary system and Mediterranean commerce. The gradual debasement that began under Nero — shaving the edges, reducing the silver content slightly — accelerated through the 3rd century AD until the coin contained almost no silver.

The economic consequences of debasement were inflation and the 'flight to quality': merchants and large commercial actors shifted to payment in gold or in kind, bypassing the debased currency for large transactions. The papyri from Roman Egypt document price inflation in the 3rd century AD that can be matched against the coin debasement record: as the silver content fell, prices in debased coin rose to maintain the same real value.

Diocletian's Edict on Maximum Prices (301 AD), which attempted to fix prices for hundreds of goods and services across the empire, was a response to this inflation — and one of the most ambitious (and unsuccessful) price control experiments in history. The edict's detailed price schedule is an invaluable document of Roman economic life even though the policy itself apparently failed quickly: merchants simply stopped selling rather than sell below cost.