The Croeseid, introduced by King Croesus around 550 BCE, is often called the first bimetallic coin.
Croeseids were issued in gold and silver versions, with the two metals struck to a carefully controlled weight relationship. This made them more consistent than earlier electrum coins, whose gold content could vary naturally.
The coins replaced Lydia’s earlier electrum currency and carried designs of a lion confronting a bull. Their standardized precious-metal content helped Croesus support reliable payments and taxation across his kingdom.
The Croeseid is often confused with the Lydian electrum stater, which is generally associated with the earliest known coinage. The distinction is that the Croeseid used separate gold and silver denominations rather than naturally mixed electrum.