The denarius became the standard silver currency of the Roman Empire.
Rome introduced the denarius around 211 BCE during the Second Punic War. It was originally a silver coin valued at ten asses, as its name reflects. Later monetary reforms changed its relationship to other denominations, but it remained one of the most familiar Roman coins for centuries.
A denarius typically carried the head of a ruler or a deity on one side and a symbolic image or inscription on the other. Imperial coins communicated political messages as well as serving in commerce. Coins could announce victories, religious claims, building projects, and succession.
The aureus was a higher-value gold coin, while the sestertius was generally a larger bronze or brass accounting and spending unit. The denarius’s silver content and purchasing power changed over time, especially as emperors reduced its precious-metal content. It eventually declined in importance during later imperial currency reforms.