Matthew Alexander's answer is very good, providing an overview of money. Because I collect ancient Roman coins, I think I should also join the discussion (always looking for a "chime in" to talk about ancient Roman coins).
Bronze ingots used after barter and before coinage are called original ingots, sign ingots and tomb ingots.
Aes raw ore looks like unrefined ore-basically.
Aes Original Sample-Source
These ingots are different in shape, size and weight, and are of little use as exchange media, so they are replaced by Aes standard.
Aes signature example-source
The signature of Aes is cast bronze with specific weight and fineness, and stamped with the government seal. Because of these standards, they are likely to be used as a medium of exchange in the 5th and 4th centuries BC.
From the middle of 4th century BC, these tombs were replaced by Aes tombs. Aes cemetery retains the standard measurement of weight and fineness, as well as the official seal of the government and the increased denomination.
Aes critical example-source
It was not until the end of 3rd century BC that these currencies were replaced by silver coins to serve China. Silver coin is a kind of silver coin, which is about the size of an American dime. This kind of silver coin became the standard currency in the next 500 years, and spread all over * * * and other parts of China until the Roman Empire in the 3rd century.
Silver coins-65438 BC+094 BC-Source
Silver coins will be used by the Republic of China to pay for troops and generals to pay for their own troops.
Silver coins minted by Caesar during the campaign-Source
As time goes on, the purity of silver coins decreases and the currency depreciates. The first person to do this was Nero, who changed the silver coin from 1 pound to 1/84 or 3. 90g reduced to 1 lb 1/96 or 3. 4 1 g. His government replaced his predecessors, especially Claudius's silver coins. Gresham's law stipulated that bad money drove out the market of good money, which made Claudius's silver coins very rare.
In the 3rd century AD, the silver content of silver coins dropped to a very low level, and the devaluation accelerated. People thought that silver coins were double silver coins. Finally, the quality of these coins is reduced to such an extent that the coins are only plated with silver on the base metal core which is easy to wear.
Anthony showed some sources of silver (AD 272-3).
Not long after Diocletian came to power, he reformed the currency, but by this time the empire was doomed, and its currency would never enjoy the power of * * * and silver coins from the late China to the middle of the first century.