The early Roman coins made from brass ,copper or bronze had clearly defined denominations with a classification system as below

AE1 coins of 28 mm diameter or larger

AE2 coins between 23 and 27 mm diameter

AE3 coins between 18 and 22 mm diameter

AE4 coins 17mm diameter and under

Republic coins   289-41 bc

Imperial coins    27 bc – 498 ad

Roman Provincial

Roman Provincial are coins that were minted in the roman empire by local authorities not by Rome.Over 600 mints flourished during the Roman Imperial era and some based their coinage on that local coins before the Romans arrived.

The majority of these coins were bronze,as the Romans controlled silver coins and didn’t want the tribal areas to control silver but they did allow the Eastern Empire to have silver coins 

Republican Coins

Before coins were struck ,trade was accomplished with cattle or rough bronze.

It wasn’t till the end of the 4th centenary that bronze was shaped into flat crude bars and did not have a standard weight.

Rome produced its first coins around 300BC,these coins were inscribed ROMANOM

(of the romans) and production continued till the end of the Punic wars in 240 BC.

Imperial Coins images on coins took an important step when JULIUS CAESAR issued coins bearing his image, this was first time a living person was on coin and was to help influence Caesars control over his empire and make him appear god like.

Many of these coins were made from silver but towards the end the silver content was lowered as silver was scarce to find and sometimes these silver coins had no silver at all, this was due ti demand for silver from india and inflation as solders pay increased for 900 sestertii under augustus to 2000 sestertii under Septimus Server and the price of grain tripled so many coins were melted .