Roman currency was introduced during the Roman Republic in 300 B.C. and was made of gold, silver, bronze and copper coins. Bronze and copper coins were used for everyday purchases whereas gold and silver coins were used for larger purchases because they had significant intrinsic value.
The bronze and later copper coin was called the as. The silver coin was called the denarius and was worth 10 to 15 asses during the Republic. It initially contained 4.5 grams of pure silver. The gold coin was called the aureus was worth 250 times the value of an as. The sestertius was worth 2.5 asses.
It is worth noting that the market value of gold and silver Roman coins exceeded the value of the precious metal that they contained. For example, the denarius was throughout the Empire 1.5 to multiple times the value of the silver that it contained. Also the amount of silver or gold contained varied especially during times of war. It significantly decreased during the 3rd and 4th century A.D..
Producing coins was a complicated process. It was complicated on purpose in order to prevent fake coins from being produced and circulated. The production of coins required special equipment and a process which produced a distinct detailed relief image free of cavities (due to oxygen bubbles) and which made the coins gloss. It also required specific quantities of (precious) metal. Romans used an almost industrial process to produce coins which were quite detailed and cleaner than Greek coins.
The equipment to make coins included casts on which liquid metal was poured in order to produce blanks (coins with no images on them). Other equipment included two die usually made of bronze. The die had the negative of the relief image to be created. The lower die usually had the image of a deity. The upper die that of a symbol of Rome. A blank was warmed in an oven. It was then placed on the lower die. Then the upper die was put above it and struck with a heavy hammer.
Initially the minting of all coins was made in the city of Rome. Later during the Empire, the minting of bronze and of some silver coins could be made at other mints at other locations. It is worth noting that all gold coins were made by only one mint situated in the city of Rome throughout the Republic and in the first few centuries of the Empire.
Coins initially featured deities. Later during the Empire they featured the heads of Emperor, noting that Caesar is the first to have started the trend of putting the head / bust of a living person on coins. Coins often had propaganda purposes.
|1 loaf of bread||0.5 sestertius|
|1 pint of (low quality) wine||0.5 sestertius|
|1 quart of olive oil||2-3 sestertii|
|1 pound of pork||32 sestertii|
|1 modius of wheat flour||10 sestertii|
|1 visit at the baths||0.25 as|
|1 tunic||15 sestertii|
|1 night with prostitute||4 sestertii|
|1 donkey||500 sestertii|
|1 slave||1,000-2,000 sestertii|
|Unskilled manual labor monthly salary (low end)||32 sestertii|
|Average Roman monthly salary||60-80 sestertii|
|Arithmetic teacher's monthly salary (per boy)||75 sestertii|
|Legionary's monthly salary||100 sestertii|
|Legionary's bonus on discharge||12,000 sestertii|
|Praetorian guard's monthly salary||250 sestertii|
|Senator's monthly salary||above 25,000 sestertii|
|Price of a small farm||100,000 sestertii|
|Price of a villa||500,000 - 2,500,000 sestertii|