Antoninianus of Caracalla
AD 215 ・ billon ・ 3rd century ・ Rome
The emperor wearing the sun's radiate crown marks the coin as "two denarii"—yet it contained only about one and a half denarius' worth of silver. Making the gap between face value and substance into an institution, this coin fell within half a century to a silver-washed copper piece. It is the protagonist of the third-century crisis.