20 Nummi - Anastasius I Dicorus Constantinopolis, Large Module

Anastasius I's currency reform of 498 AD was one of the most consequential fiscal decisions in Byzantine history. Prior to it, the late Roman bronze coinage had deteriorated into tiny, nearly valueless nummi that functioned more as accounting units than actual money. The reform reintroduced large, clearly marked bronze denominations — the follis, half-follis, and this 20-nummi piece — explicitly stamped with their value so that illiterate users could transact without ambiguity.

The "large module" designation distinguishes these early post-reform strikes from later, reduced flans issued under Justin I and Justinian I, when the physical size of bronze coinage crept downward again.