The as, occasionally assarius, was a bronze, and later copper, coin used during the Roman Republic and Roman Empire.
An etching of a Roman Republican as
Nero as
The dupondius was a brass coin used during the Roman Republic and Roman Empire valued at 2 asses.
Sestertius of Hadrian, dupondius of Antoninus Pius, and as of Marcus Aurelius
Dupondius of Vespasian (69–79), struck at Lyon in about 72–73. This coin seems to have escaped the serious corrosion typically observed in ancient coins and thus retains nearly its original appearance and colour, showing why the Romans sometimes also called this alloy aurichalcum, from aurum for gold in Latin+"-chalcum" as in the most widely used orichalcum. The coin measures about 29mm in diameter.
Image: 0201trajan
Image: Faustina II