The sestertius or sesterce was an ancient Roman coin. During the Roman Republic it was a small, silver coin issued only on rare occasions. During the Roman Empire it was a large brass coin.
Example of a detailed portrait of Hadrian 117 to 138
Hostilian AD 251
Sestertius of Hadrian, dupondius of Antoninus Pius, and as of Marcus Aurelius
A sestertius of Nero, struck at Rome in 64 AD. The reverse depicts the emperor on horseback with a companion. The legend reads DECVRSIO, meaning "a military exercise". Diameter 35 mm
Roman currency for most of Roman history consisted of gold, silver, bronze, orichalcum and copper coinage. From its introduction during the Republic, in the third century BC, through Imperial times, Roman currency saw many changes in form, denomination, and composition. A feature was the inflationary debasement and replacement of coins over the centuries. Notable examples of this followed the reforms of Diocletian. This trend continued with Byzantine currency.
Denarius of Marcus Aurelius. Legend: IMP. M. ANTONINVS AVG. TR. P. XXV.
Bronze aes signatum produced by the Roman Republic after 450 BC
Coins of the Roman Republic and Empire from Cassell's History of England, Vol. I
The rapid decline in silver purity of the antoninianus
