A mint is the workshop where coins were struck. In antiquity, different cities of the Empire struck their own metal, and each left marks that today let us know exactly where a piece was born.
That provenance matters: two identical coins can have very different values depending on their mint, rarity and die quality. Reading the mint mark is the first step to understanding a piece.
How to read it
Marks usually appear in the exergue — the lower band of the reverse — as letters or symbols. In our historical records we always note the mint, alongside the emperor, year and catalogue reference.