Who They Were
Thomas Gresham (1519–1579) was an English merchant and royal financier whose observation about currency became known as Gresham's Law: "Bad money drives out good." When debased coins circulate alongside high-quality coins, people hoard the high-quality coins and spend the debased coins, eventually driving quality currency from circulation.
Core Contribution
Gresham's Law explained why currency debasement by rulers was economically destructive. When governments debase coinage, citizens respond rationally by hoarding the remaining good coin, causing a currency shortage and economic disruption.
Impact & Legacy
Gresham's Law became foundational to monetary economics. It explains why stable currency requires commitment to maintaining metal content and quality. The principle appears throughout monetary history.
Why They Matter Today
Gresham's Law remains relevant. Modern examples include cryptocurrency ("good" digital assets hoarded when inflated fiat currencies circulate) and the hoarding of stable currencies during periods of high inflation.