The expense of quadrans

[PeterD]

Surely all bronze coins had only token value, as their values were expressed as a fraction of a silver coin rather than the value of the metal they were made of?

[Diederik]

Yeah, but you would expect them to  weigh accordingly to their status: 10, 5 and 2.5 grams (or less accordingly)

Frans

[basemetal]

To make any currency system work,  and this is much simplified,  all that is required is that a majority of its users all agree that it is worth such-and-such. 
The often mentioned fact that ancient coins are difficult to value in terms of their ancient buying power because they represented the metal they were minted of, is only partially true, I feel.  In a world without denari (or where a minority have them and/or aureus and similar), the holder of the sestertius may be king, so to speak.

[PeterD]

To make any currency system work,  and this is much simplified,  all that is required is that a majority of its users all agree that it is worth such-and-such.

I think that's quite right. Value is a relative term. If you imagine the very first coins made; a lump of metal such as silver of a fixed weight was stamped with an official mark. That lump of silver (a coin) was then the preferred medium of exchange compared with an unmarked piece of silver of the same weight. In other words, a silver coin had a greater value than the same weight of silver bullion. If that wasn't the case, the use of coins would never have taken off.

Skipping forward to the Roman period, provided the coinage remained overvalued (or conversely bullion silver remained under valued) the system remained stable. The system could even take some de-basement and reductions in the weight.

Of course, the whole system went pear-shaped in the 250s. One of the main problems must have been that the 'silver' coinage could no longer pegged to the gold coinage. This must have split the system into two economies, gold which could be used for long distance trade and the rest which could only be used much more locally.

It seems possible that the Sestertius, because of it's imposing and unchanged size was regarded as a an alternative to the nasty small Antoninianii - a case of 'user confidence' - because double Sestertii (if that's what they were) were produced at greater weights. Ultimately, of course, that didn't work out either.

[basemetal]

A  question:
When was the last approximate date that the large sestertius say of 250 years previous would still hold value as a coin as opposed to it's metallic value.  The 250 years figure is a misonomer, I don't know the date.
What I'm asking is what's the last approximate date that you could go to a market and spend a large sestertius of say, Trajan as a legitmate coin  as opposed to it being seen as "a large, fairly valuable piece of bronze"?

[Diederik]

In my opinion it is likely that until Diocletian's reform, big pieces were part of the currency. Aurelian was the last to mint big-size coins and that was only just before the reform. The output of Gallienus was small, but Postumus minted big bronzes in relatively large quantities. These coins, when up for sale or auction, are usually pretty worn, which might suggest a long life.
The only comparison I can draw with big bronzes are British pennies: in the sixties when I tried to find good/reasonable quality coins of Edward VII and Victoria, this was virtually impossible, meaning that big bronzes wear down in approximately 50 to 60 years. Perhaps that the overall quality of late Third-century big bronzes gives a hint to answering your question.


Frans

[PeterD]

250 years is not a bad figure. A hoard found in 2003 at a place called Nevill Holt, Leicestershire contained 253 bronze coins  dating from Augustus to Postumus with most intermediate emperors in between. 61 of those were 'uncertain', i.e. too worn to recognize, and 16 contemporary copies.

From at least the 250's , because of de-basement, the value of the antoninianus and it's fractions could no longer be defined by a fixed ratio to gold. Therefore they were effectively 'floating' and their value was simply what they could buy (which was becoming less and less). Anyone just had to look at an antoninianus to see that it had decreased in value, whereas bronze coins looked much the same as they always did. I doubt if there was any official change in their relative values, but I can imagine signs going up in shops saying "Sestertii only accepted here!".

I don't think that bronze coins ever went from being coins to being 'bartered bullion'. It may be that their intrinsic value ultimately took them out of circulation as happened with the silver coinage.