They are coins minted within the Roman Empire by local civic authorities (cities, colonies or provinces), rather than by the central imperial mint.
These coins often maintained local traditions, such as Greek inscriptions in the eastern provinces, and often continued the types and denominations prior to Roman rule.
They were issued primarily in bronze, although in some eastern regions there were also issues in silver and billon, but never in gold. Provincial Roman coins were never made of gold because the Roman state reserved the exclusive right to mint gold and silver coins, especially gold, to ensure the stability and control of the imperial economy.
Their circulation was local, that is, they were intended for everyday use in the province or city where they were minted, and they were not legal tender throughout the empire like imperial coins.
