Medieval coinage was often decentralized, with local lords minting their own versions. The Industrial Revolution introduced steam-powered presses, like those developed by Matthew Boulton and James Watt , which allowed for perfectly uniform coins with reeded edges to prevent "clipping" (shaving off metal). How Coins are Made: The Modern Minting Process

Developing independently, the Chinese were the first to use copper coins, famously casting them with square holes in the center so they could be strung together for easy transport.

The Greeks advanced the artistic side of coinage, depicting gods and mythological figures, while the Romans were the first to use coins as mass propaganda, spreading the image of the Emperor across vast territories.