From AD 64, during the reign of Nero and again under Vespasian, the mint of Lyon (Lugdunum) supplemented production of aes coinage.

The brass sestertius typically weighs about 25-28 grams, measures about 32-34 mm in diameter, and is about 4 mm thick. Romans distinguished bronze from brass, calling brass orichalcum, also spelled aurichalcum, a term that alludes to its gold-like color when newly struck.