Sestertius

The sestertius (plural: sestertii) was the large brass denomination that became the prestige coin of the Roman imperial series. Under Augustus the sestertius was reformed as an orichalcum (brass) coin of approximately 25–28 grams and 30–35mm diameter — a size that gave die engravers room for the most detailed and artistically ambitious compositions in Roman coinage. The denomination was worth four asses or one quarter of a denarius. Sestertii were struck primarily at the Rome mint, with the letters SC (Senatus Consulto) appearing on the reverse to indicate senatorial authority over base metal coinage. Production continued until the late third century, though quality and weight declined sharply after the Antonine period. For collectors, sestertii represent the finest portrait art in Roman numismatics — the large flan allowed detailed rendering of imperial features, elaborate reverse scenes, and architectural types that are impossible to appreciate on smaller denominations. Condition is critical: well-preserved sestertii with smooth olive or brown patina command significant premiums. The standard references are RIC and BMCRE by reign period. Notable types include the Judaea Capta sestertii of Vespasian, the architectural sestertii of Trajan, and the province series of Hadrian.