If you have visited the spellbinding British Museum exhibition Life and Death in Pompeii and Herculaneum you will have, no doubt, rightly been overawed by the wealth of wonders on display; pristine bronzes, dazzling frescoes, even human remains, all eerily preserved by the ashes spewed from Vesuvius on that fateful day: 24th August 79 CE. A date we have been taught in school, read in textbooks and seen in film & television; truly “a date that will live in infamy”.

Or not. Even after visiting the exhibition, many may not realise the long accepted date of the eruption is even in doubt (I saw the topic briefly mentioned a couple of times in item descriptions) let alone that there exists a key piece of evidence that puts the date to bed definitively. Evidence that was sadly (for me, anyway) absent from the exhibition.

Firstly, you may ask from where the traditional eruption date of 24th August originates? In a letter [6.16] to Tacitus (written 25 years after the event), our old friend Pliny the Younger describes the eruption that took place on “Nonum Kal September” or “the ninth day before the Kalends of September” i.e. August 24th. Yet these modern interpretations stem from questionable 16th Century translations, from authors who would have struggled to understand the dating conventions used in the original manuscripts. Manuscripts which in turn, may have been corrupted themselves. Even though ancient historian Cassius Dio directly states that the disaster took place “towards the end of the harvesting season” (the harvest began in October), a 1508 translation of Pliny’s letters settled on an August date for the disaster and the rest is history.

Despite this, scepticism for this summer eruption date has actually been widespread since the first large scale excavations in the 18th Century. Circumstantial evidence pointing to late-Autumn date abounds:

The fresh fruit and vegetables for sale on the day of disaster are unseasonal for August.

The expected summer fruits had been dried for preservation.

The October grape harvest and wine making season was completed with wine already sealed in jars.

Citizens were dressed in unseasonal warm clothing (though possibly due to conditions during the eruption).

Many homes were using wood burning heaters at the time of eruption.

Long term studies of wind directions around the Bay of Naples have deemed the manner in which ash was distributed consistent with a post-September eruption date.

This accumulated evidence is convincing and easily understood by a lay audience, yet the most conclusive piece of evidence has received little fanfare and actually lay in a museum vault for over 30 years before anyone noticed its significance.

On 7th June 1974, during excavations of Pompeii’s “House of the Gold Bracelet”, a selection of 180 silver and 40 gold coins were discovered with the bodies of a group of victims. The coins were found in a stratified archaeological context that attested to them being buried in the initial stages of eruption (and not subsequently dropped by looters or treasure hunters). Though an impressive find, the discovery of coins on such a bountiful site was not earth shattering news and the un-catalogued coins were sent for safe keeping in the vaults of Naples Archaeological Museum.

They lay in this archaeological limbo until 2006 when an expert (Grete Stefani, Boscoreale Antiquarium) finally got round to cataloguing them and made an amazing discovery. Amongst the standard coin types was a single denarius from the reign of Titus, emperor at the time of eruption and remembered fondly for the relief efforts he organised in its wake. No surprise in itself; coins of the ruling Flavian dynasty were flowing into Pompeii at the time of the eruption and have been found everywhere. The problem: this issue of coin should not have been.

In a testament to the wonderfully precise dating evidence that coins provide (often exact to a window of weeks, let alone months or years) the denarius proclaims the latest collected titles of the victorious Emperor Titus (79-81), the dates of which can be corroborated from inscriptions around the empire to a high level of accuracy.

It declares: TR P VIIII IMP XV COS VII PP (“with the tribunician power for the ninth time, acclaimed emperor for the fifteenth time, consul for the seventh time, Father of the Nation”). We know from separate contemporary sources and letters that Titus did not receive his 15th Imperial acclamatio until September 79 CE (likely for achievements in Britannia), upon which new coins would have been minted and dispersed to mark this unplanned event.

It may not be a great monument or life size bronze but the evidence this coin provides is diminutive and definitive. Frankly odd descriptions of the coin being “barely readable” make no sense as it would have been all but a few weeks old and in pristine condition at the time of eruption. Drawings show a coin in mint state:

That such dramatic conclusions can be drawn from such a tiny object may be difficult to comprehend but such are the joys of history. It may not be the discovery of an iPod in a Pharaoh’s tomb but there is no reasonable scenario that would explain this coin existing in Pompeii in August 79 CE.

Now you would assume a discovery with such historical significance would have been much celebrated in the last few years? You would assume wrong. As one who appreciates ancient coinage but also just as a lover of history, it surprises me that to date not a single photograph of the coin has been published, only drawings exist. Little to no documentation can be found about it online and the coin itself has not left the Naples Museum. Some have even gone so far as to question whether information about the coin is being intentionally suppressed, rather than having to change all those textbooks!

Back to Life and Death in Pompeii and Herculaneum; I fully appreciate that when planning an exhibition for the public, even the most hardened academic would likely opt for a full-size statue rather than a single silver coin 20mm across. Likewise an item such as a gold ring provides an instant emotive and universal understanding that needs no explanation, whilst a tiny coin and the complex deductions that can be made from its alienating impersonal ancient jargon – not so much. Nevertheless. It would have been splendid to see the ancient object that finally debunked the oft-cited August eruption date of Vesuvius, or at least an enlarged image of it with up-to-date conclusions.

Granted, this was an exhibition not about the eruption but about people; their lives and their deaths; with that mission statement, the exhibition is a soaring success. But you can be sure if the eruption date was written in graffiti on a brothel wall, it would have been included.