When Was Pompeii Destroyed? The Date Debate

We have an eyewitness, a date and a letter, and still nobody can agree on when Vesuvius erupted.

In AD 79, Pompeii, a town on the Bay of Naples, was destroyed when Mount Vesuvius erupted. The volcano sent pumice in the air followed by clouds of hot ash and gas that flowed down the slopes, enveloping houses, temples, streets and many of those who had remained.

The nearby town Herculaneum suffered the same fate. Based on archaeological findings, we know that the remains of over 1,400 people have been found (around 1,150 in Pompeii, around 300 in Herculaneum), but we can't say what the true total was. There are probably many more remains buried and, given that population estimates for the two towns run to 20,000 or more, there could have been many more fatalities.

Much of what we know of the disaster comes from two letters sent to the historian Tacitus. Pliny the Younger, watching from across the bay, described the events as he saw them unfold. He reported how his uncle, Pliny the Elder, sailed towards the danger and died at Stabiae.

Today Pompeii is visited by millions of people each year and is one of the most famous historical disasters to have befallen humanity. Pliny the Younger's eyewitness account and, more importantly, the buildings preserved under ash, give us a great deal of information, helping archaeologists and historians piece together a lot of what happened. But there are still gaps in our understanding and one of the most contested points is the actual date of the eruption. When was Pompeii destroyed?

When Was Pompeii Destroyed? The Date in Pliny's Letters

There are several possibilities for the date of eruption, ranging from August to November. The year AD 79 is widely accepted. The date traditionally given for the disaster is 24th August. This is sourced in one of the letters from Pliny the Younger to Tacitus (Epistles 6.16).

Loosely translated, this means "at about the seventh hour of the ninth day before the Kalends of September, my mother points out to him (Pliny the Elder) that a cloud, unusual in size and shape, is appearing."

The Romans' rather complicated way of expressing dates involves subtracting days from the next marker day (Kalends, Nones or Ides). In this case, the marker day is the Kalends (1st September), giving a date of 24th August.

If this is the date for the cloud first appearing in the sky, then it still leaves doubt as to the final date of Pompeii's destruction. If the eruption lasted a day or so then the date in question might be more accurately 25th August. We then need to take into account the time gap between Pliny the Younger witnessing the event and writing it to Tacitus decades later. It is possible that he misremembered the date over the intervening years.

What the Surviving Manuscripts Say

There's also another, more significant issue. Over the centuries, different versions of the letter were created by scribes who copied the words by hand, introducing changes in the text which have persisted. One of the oldest manuscripts, Codex Laurentianus Mediceus, dating from the 9th century, offers the ninth day before the Kalends of September (24th August). Yet later copies of the same book give the Kalends of November (1st November) as the date.

According to Bryn Mawr Classical Review, Pedar Foss, a classicist at DePauw University, reports in his book Pliny and the Eruption of Vesuvius (2022) that the oldest and best copies of the letter give 24th August as the date. Another review of the same book by Scarpati at the University of Naples Federico II reports that Foss has studied inscriptions, coins, plant remains and climate evidence to land on his support for the August date.

Was the Original Date Different?

Another hypothesis is that the original date was neither of those given in the copies of the letter. Archaeologists Borgongino and Stefani, according to the Bryn Mawr Classical Review, propose that the date of the eruption is 24th October.

As already mentioned, the two main readings of the date in the letter are 24th August, the best supported, and 1st November. The October date comes from the theory that the letter originally said "the ninth day before the Kalends of November", which would mean 1st November minus eight (since the Kalends counts as day one) giving 24th October. No surviving copy of the letter actually shows the date written in this way. Foss also rejects this date, saying the 24th October camp try to bend "a corrupt date from the least reliable manuscript family".

A paper published in the Journal of Volcanology and Geothermal Research 169 (2007) (Rolandi, Paone, Di Lascio and Stefani) supports an autumn date. It argues that the way the ash spread is consistent with autumn and winter winds, and that the discovery of mature pomegranate peel at Oplontis and fruit residues in excavated sites indicates an autumn date too. Heavy clothing and braziers have also been found, again supporting colder weather.

Another piece of evidence the authors of the paper put forward is the discovery of a silver coin in Pompeii which they say shows the 15th acclamation of Titus. If the 14th acclamation happened on the 7th or 8th of September AD 79 as evidenced in two documents (a bronze letter from Munigua and a military diploma from Egypt), this would rule out an August eruption date.

Other scholars who disagree with the October date say the fruit findings have been used to argue for an August date before (Ciarallo and De Carolis, 1998) and question the reading of the Titus coin (Abdy, 2013). When Abdy re-examined the coin, he read it as the 14th acclamation, not the 15th, meaning an August eruption would be possible. Flavio Altamura argued the same.

Another point of interest revolves around a charcoal inscription found in 2018 on the wall of a house in Pompeii. The text includes a date XVI K NOV, which is 17th October. Now, if that date was written in AD 79, then that would rule out 24th August as the eruption. Archaeologists argue that charcoal writing does not persist for long, meaning it would have likely been written in AD 79.

While an interesting piece of evidence, it is not conclusive. The lack of a year with the date is a problem (e.g. it could have been written in AD 78) and charcoal can apparently last for years if it is protected from the weather or people.

So When Did Vesuvius Erupt?

It is an interesting debate and one that I had not considered until researching a video about Pompeii. On one side we have Pliny the Younger's letter. Copies of this give us two dates, 24th August and 1st November, and a third date appears if we accept the theory that the original letter actually said "the ninth day before the Kalends of November", or 24th October.

On the other we have the evidence found in Pompeii and the surrounding area, showing autumn fruits, heavy clothing and braziers. The charcoal inscription may also add weight to an October eruption.

Weighing up the evidence as best I could, I came to the conclusion that autumn made the most sense to me. Unfortunately, unless we excavate more conclusive proof, it will remain an educated guess.

Frequently Asked Questions