The Denarius

This was the most common early Roman coin. It was first minted in 211BC of silver with a weight of 4.5 grams. It was then reduced to a weight of 3.9 grams until the time of Nero after which it was slowly debased over the centuries to a last bronze issue by the time of Diocletian.

A denarius was originally valued a 1/25 of a gold aureus and equivalent to 10 bronze asses.

Even after the coin was no long minted the denarius was still used as a unit of account and eventually was the basis for the silver penny (or dernier in France).