From Sinuessa to Misenum the coast forms a vast gulf; beyond this is another gulf still larger, which they name the Crater. It is enclosed by the two promontories of Misenum and the Athenæum. It is along the shores of these [two gulfs] that the whole of Campania is situated. This plain is fertile above all others, and entirely surrounded by fruitful hills and the mountains of the Samnites and Osci. (Strabo, Geographica)

Volcanology can be traced back to Campania. The first detailed report of an eruption was made here, in the year 79, by an 18-year old boy called Pliny. To avoid confusion with his uncle, a major person in the navy, he was known as Pliny the Younger. Strictly speaking, the additive could have been dropped afterwards since his uncle was one of the many people who died in the eruption. But instead, the name stuck.

People

His uncle is known as Pliny the Elder, which already shows that the boy would go on to make a name for himself. The older Pliny’s full name was Gaia Plinius Secundus (so in a way he also was a ‘younger’). He was a scientist by nature, and produced a huge series (37 volumes – not all survive) called Naturalis History (Natural History) which really tried to cover everything – if you wanted to know what use a particular plant was, you could look it up in here. Much of the content came from what was written in other books: Pliny the Elder was the AI of his time. And like modern AI, not all the fact checking was complete. People with umbrella-shaped feet did not really exist. Clearly Pliny the Elder was a voracious reader. Or rather, he was a voracious listener, since he would get his slaves to read the books to him. Glasses did not exist in those days! (In UK Academia, the title ‘Reader’ still exists. It is equivalent to a junior professor in the US, and one step below full professor.) But he also acted on his own curiosity. Pliny the Elder died getting too close to the Vesuvius eruption, both to help people and to get a better look! ‘Fortune favours the Brave’ he reportedly said during the mission.

Pliny the Elder was also a high ranking official in the Roman Empire. He had served in Germany together with Titus, who would later become Emperor. He was a close advisor to another emperor, Vespasian, and he was in charge of the main Roman navy in the Mediterranean, as Prefect of the Fleet. The main base of this fleet (Classis Misenensis) was at Misenum, nowadays known as Miseno, located on the tip of the peninsula southwest of Pozzuoli. Pliny the Younger was staying with him at the time, with his mother. The likely location of the villa was recently identified. The location gave a direct view over the two harbours, the inner harbour for parking ships for the winter (Mare Morto – dead sea), and the outer harbour for exercises. The site also gave a view across the Bay, including Mount Vesuvius, 30 km away.

Pliny the Younger’s full name was Gaius Plinius Caecilius Secundus. He was not born with that name, though. His father died early, and he was later adopted by Pliny the Elder, the brother of his mother. Because of that adoption, he changed his name. But that adoption only happened in the will of Pliny the Elder (in which he also inherited the estate). Thus, this was immediately after the eruption of Vesuvius, and during the eruption he wasn’t called ‘Pliny’ yet. After Vesuvius he moved to Rome where he married (we don’t know to whom: he had two or three marriages over his life), became an administrator, later a prosecutor and consul, and finally Governor of a province in Asia Minor where died, at the age of around 52. We know of him mainly through his many letters. They depict life in and around the senate in Rome, over a time when the Roman Empire slowly became more authoritarian. His letters grow pessimistic towards the end of his life. Rome’s greatest time was also when the faults that would later weaken the empire crept in.

Letters

Two of the letters are about the Vesuvius’s eruption, and especially the death of his uncle, later his late father. Those letters were written around 100 AD, some 20 or 25 years after the events. They were written to his friend Tacitus, who had asked for a detailed account for his book Historiae (Histories). But although we have much of the Histories, the ones detailing events after 70 AD are lost. We have the letters about Vesuvius from Pliny’s own publications, but not from the books for which they were written.

What do the letters say? Let’s see!

petis ut tibi avunculi mei exitum scribam, quo verius tradere posteris possis. gratias ago; nam video morti eius si celebretur a te immortalem gloriam esse propositam.

Of course, they were written in Latin, a language not all VC readers may know. Luckily, translations are readily available:

“LXV – TO TACITUS

Your request that I would send you an account of my uncle’s death, in order to transmit a more exact relation of it to posterity, deserves my acknowledgments; for, if this accident shall be celebrated by your pen, the glory of it, I am well assured, will be rendered forever illustrious. And notwithstanding he perished by a misfortune, which, as it involved at the same time a most beautiful country in ruins, and destroyed so many populous cities, seems to promise him an everlasting remembrance; notwithstanding he has himself composed many and lasting works; yet I am persuaded, the mentioning of him in your immortal writings, will greatly contribute to render his name immortal. ”

And so on. Pliny the Younger was a gifted orator and a beautiful writer, but nowadays we write rather more direct (‘simpler’, some would say) and this style of writing can be hard to read for us. I asked Gemini for a simpler version – simplifying things should be just what AI is written for! It suggested various styles, of which ‘polite professional’ seemed best suited for VC. It even put in headings, which weren’t there in the original. I took them out again. Here we go. The first letter is about the demise of his beloved uncle:

LXV – TO TACITUS

“Thank you for asking me to write down the details of my uncle’s death so future generations can have an accurate account. Honestly, if a writer like you covers this story, I know it will be remembered forever. Even though he died in a massive disaster that wiped out entire cities—which usually keeps a name alive—and even though he wrote plenty of books himself, being mentioned in your work is what will really make him a legend. They say some people are lucky enough to do great things, and others are lucky enough to write about them. My uncle was one of the rare few who did both. I’m more than happy to do this for you; in fact, I would have offered if you hadn’t asked first. At the time, he was in command of the fleet at Misenum.

On August 24th, around 1:00 PM, my mother noticed a very strange cloud and pointed it out to my uncle. He had just finished a cold bath and lunch and was working on his books. He stood up and went to a viewpoint to get a better look. From that distance, we couldn’t tell which mountain the cloud was coming from, though we later found out it was Vesuvius. The cloud looked like a giant pine tree—it shot up like a massive trunk and then spread out into branches. It was sometimes white and sometimes dirty and spotted, depending on whether it was carrying earth or ash.”

“Being a man of science, my uncle thought this was a phenomenon worth investigating up close. He ordered a light galley to be prepped and told me I could come along if I wanted. I told him I’d rather keep working on my studies, and as it happened, he had actually given me a writing assignment earlier.

Just as he was leaving the house, he got a frantic note from Rectina, the wife of Tascus. Her villa was right at the base of the mountain, and there was no way out except by sea. She was terrified and begged him to save her. This changed his whole plan: what started as a scientific trip became a heroic rescue mission.

He launched the large warships and headed straight toward the danger zone to rescue Rectina and many others, as that stretch of coast was very popular. He steered right into the thick of the disaster, completely unafraid, even dictating notes on every shift and shape of the eruption as he saw it.

As they got closer, the ash falling on the ships became hotter and thicker. Then came pieces of pumice and black, charred stones. Suddenly, the water became shallow, and debris from the mountain blocked the shore. His captain urged him to turn back, but my uncle famously said, ‘Fortune favours the brave! Head for Pomponianus at Stabiae.’

They reached Stabiae, where his friend Pomponianus was already loading boats to escape as soon as the wind shifted. My uncle hugged his trembling friend and tried to calm him down. To make everyone feel less nervous, he acted like everything was normal—he went to the baths, sat down for dinner, and was genuinely cheerful (or at least did a very good job of faking it).

Meanwhile, massive sheets of flame and fire were breaking out all over Vesuvius. To ease the panic, my uncle told everyone it was just abandoned villages or farmers’ fires burning out of control. Then, he actually went to sleep; people outside his door could hear his loud snoring.

Eventually, the courtyard outside his room filled up with so much ash and stone that if he had stayed any longer, he would have been trapped. They woke him up, and he joined the rest of the group. They debated whether to stay indoors or try their luck outside, as the whole house was swaying from the constant tremors. They decided to head for the shore, tying pillows to their heads with sheets to protect themselves from the falling rocks.

It was daylight everywhere else, but there it was darker than the deepest night, broken only by torches and flashes of fire. He went down to the water to see if they could escape, but the sea was still way too rough. He laid down on a sailcloth and asked for cold water twice. Then, a smell of sulfur signaled an approaching fire, and his companions scattered. He stood up with the help of two servants but immediately collapsed. I believe the thick fumes blocked his breathing. When light finally returned three days later, they found his body completely intact. He looked less like a dead man and more like someone who was just fast asleep.”

The second letter is about himself, although it still ends with his uncle.

“After my uncle sailed away, I spent the rest of the day studying—since that was why I had stayed behind—followed by a bath, dinner, and a very restless sleep. For many days, we’d been feeling earth tremors, but they didn’t alarm us much because they’re common in this part of Italy. However, that night the shaking became so violent that it felt like everything was being overturned rather than just moved. My mother rushed into my room just as I was getting up to wake her. We sat in the courtyard, and I—with the strange confidence of a teenager—called for a book of Livy and started reading and taking notes as if nothing was wrong.

By 6:00 AM, the light was faint and eerie. The buildings around us were shaking so badly that we were in constant danger of them collapsing. We finally decided to leave the town. A panicked crowd followed us, pushing and shoving as people usually do when they’re terrified. Once we got clear of the houses, we stopped. The carriages we had ordered were rocking back and forth on level ground, and even when we jammed them with stones, they wouldn’t stay still. The sea seemed to be sucked back into itself, leaving sea creatures stranded on the dry sand. On the other side, a terrifying black cloud was shredded by bursts of fire, revealing massive sheets of flame.

Soon, the cloud began to descend and cover the sea. My mother started begging me to leave her and run for it, saying that as a young man I could make it, but she was too old and slow to keep up and didn’t want to be the reason I died. I told her there was no way I was surviving without her. I took her hand and forced her to keep walking. She gave in, but she kept apologizing for slowing me down. Then, the ash began to fall—not a lot at first, but enough to be noticeable.

I looked back and saw a thick, black fog rolling over the land behind us like a flood. I suggested to my mother that we get off the main road while we could still see, so we wouldn’t be trampled by the crowd in the dark. The moment we sat down, total darkness hit. It wasn’t like a moonless night or a cloudy sky; it was like being in a sealed room with the lights turned out.

You could hear the shrieks of women, the crying of babies, and the shouting of men. People were calling out for their parents, children, or spouses, trying to recognize them by their voices. Some were praying for death because they were so afraid of it; others were convinced the gods had abandoned the world and this was the end of everything.

A faint light appeared, but it wasn’t the sun—it was just the fire getting closer. Luckily, the fire stayed a bit of a distance away, and we were plunged back into darkness and heavy falling ash. We had to stand up every few minutes to shake it off, otherwise we would have been buried and crushed by the weight of it.

Eventually, the darkness thinned out into a sort of smoky haze, and the sun actually came out, though it looked sickly and dim, like during an eclipse. Everything we saw was buried in deep ash, looking like a heavy snowfall. We went back to Misenum, and even though we were still shaken and the tremors were continuing, we refused to leave until we heard news about my uncle.”

Locations

The map below indicates the main locations of the events: Misenum (north side of Capo Miseno, indicated by the ship symbol), Stabiae (look for Castellammare di Stabia, eastern tip of the bay), Vesuvius, and of course Pompei. Herculaneum is located at Ercolano. Neither of the latter two are mentioned in the descriptions. They were forgotten after the eruption, deeply buried without survivors. That is typical for major, ancient eruptions: we only have stories from people far enough away to survive, and not from areas where there were no survivors. It can make those eruptions appear less bad than they really were. I think it is one reason why we know so little about the Rinjani eruption – or Iceland’s Eldgja!

Misenum was a major port and cultural centre. Even the emperor would stay here. Nearby Bacoli had a reputation like Las Vegas! The inner bay was separated from the outer one by a spit, through which a channel had been dug. The villa that has been (tentatively) identified as that of Pliny the Elder is located near the Theatrum, along the south side of the outer harbour. The road over which they fled in the morning would have been the Schola Armaturarum. The receding sea which is mentioned would have been the open Mediterranean, on the west side of the peninsula.

Stabiae was another Roman port on the opposite side of the Gulf of Naples. It is known for its seaside villa, used by the Roman elite and strecthing over several kilometers. Misenum could be seen from those villas. There were other wealthy villas a bit in-land, acting as farmhouses often with vineyards. It seems one of those coastal villas that is mentioned in the story of Pomponianus.

Stabiae became buried under ash but was rebuild. The location was too beautiful to surrender to a mere volcano!

Stabiae had not been Pliny’s intended landing point. Pliny the Elder was aiming for the villa of ‘Rectina, wife of Tascus’ but was unable to reach there. We know nothing about them other than the names and that they lived at the base of the mountain. That may have been at Herculaneum but there were villas along much of the coast line. It seems possible that Rectina did not survive. We don’t know what the rest of the Roman fleet that had been send out on the rescue was doing, but presumably they had run into the same problem as Pliny’s smaller (but faster) ship.

Volcanoes

The Romans knew about volcanoes. They also knew that Vesuvius had been a volcano, because of the ash and pumice found in the fields around the summit. But the mountain had not erupted in Roman times. Diodorus Siculus (80–20 BC) reports that the Campanian plain was called “Phlegrean (“fiery”) from the mountain which of old spouted forth a huge fire as Aetna did in Sicily; at this time, however, the mountain is called Vesuvius and shows many signs of the fire which once raged in those ancients times.”

Strabo’s Geographica lists 10 volcanic locations, islands, or features, known in Roman times:

Italy:

1. Etna (Sicily): Described as a major volcano.
2. Lipari Islands (Aeolian Islands): Including Stromboli and Vulcano.
3. Ischia (Pithekoussai): Mentioned as a volcanic island near Naples.
4. Vesuvius (Mount Vesuvius): Noted for its volcanic appearance before its famous 79 AD eruption. Campi Flegrei was included in the location

Turkey:

1. Catacecaumene (Land of Burned-Out Volcanoes): Located in Asia Minor (modern Turkey).
2. Mount Argaeus (Erciyes Dağı): A high mountain in Cappadocia with volcanic activity.

Greece:

1. Methana (Peloponnese): A peninsula with hot springs and volcanic vents.
2. Thera (Santorini): An island famously known for its ancient caldera eruption.
3. Melos (Milos): A volcanic island in the Cyclades.
4. Nisyros: A small Greek island with a dormant volcano.

Strabo noted that these areas were known for “fire,” hot springs, or “ignited matters” (sulfur, bitumen), which he accurately attributed to volcanic activity. Interestingly, these volcanoes were mainly non-erupting. The Romans were familiar with Etna and with Stromboli and Vulcano, so knew the eruptions patterns for them. The most damaging one was Etna, but even there the eruptions were manageable. In the words of Virgil (Eneid, Bk. 3), in the free translation of Conington:

“But Etna with her voice of fear
In weltering chaos thunders near.
Now pitchy clouds she belches forth
Of cinders red, and vapour swarth;
And from her caverns lifts on high
Live balls of flame that lick the sky:
Now with more dire convulsion flings
Disploded rocks, her heart’s rent strings,
And lava torrents hurls to-day
A burning gulf of fiery spray.”

2000 years later, that still describes her eruptions pretty well. But there were exceptions. The Romans had experienced only one comparable eruption: Mount Etna in 122 BC. It was an explosive VEI-5 eruption which had pelted Catania with tephra to such a degree that houses collapsed. This eruption formed a large crater at the summit, where the new (currently active) cones later developed. Other than this, the Romans were not familiar with the real dangers of explosive volcanism.

Warnings

There is one clear indication of precursor activity in Pliny’s letters. He writes that “For many days, we’d been feeling earth tremors”. They were ignoring them because earthquakes were common. But it does sound like the activity went beyond the usual.

We know from archaeology that there had been one other warning, albeit not in Misenum. In Pompei, the viaduct that brought in the water had failed, and a new one was being constructed. Models indicate this could have been caused by inflation at Vesuvius. The water viaducts were build with a precise downward slope. Even moderate inflation could have rendered it inoperable by changing the slope, as the viaduct skirted Vesuvius. The problem had been going on for a while, based on the on-going reconstruction.

There is also evidence of earthquake damage in Pompei. Some of this may be due to the major event in 62 AD, but reconstruction activity in various villas suggests more recent damage.

Eruption

The letters of Pliny the Younger are the only direct description we have of the eruption. It was also the first time such an explosive eruption had been reported in any detail, of what is now called a Plinian eruption. The name does not specify which Pliny!

There is a clear sequence of events. The first eruption that was seen in the early afternoon was a typical large eruption column. It led to Pliny the Elder readying the fleet to help. The message from Rectina came near that time, even though it would have taken a while to arrive. The problems near Pompei started earlier, badly enough to call for help to evacuate. This may have been earthquakes – the letter does not say.

Crossing the Gulf of Naples in the ships of the time would have taken several hours, and probably longer because of the difficult conditions and change of destination. As Pliny the Elder sailed into the Bay, ash fell with pumice and stones at increasing temperatures. This will have been subsequent explosions to the initial one. Finally, the water became shallow and filled with debris. This sounds like pumice rafts. During the afternoon, the eruption had grown into a major one. The wind was on-shore: we know that because Pomponianus was unable to launch his ship because of the wind direction. This may have been caused by the eruption itself: the rising eruption column can pull in ground-level air around it. The letter mentions massive sheets of flame and fire. The cause is not made clear. Most likely it is the hot pumice thrown out by the eruption, causing fires on the flanks. It wasn’t lava, as there is no evidence for lava flows associated by the eruption.

Pliny the Elder slept overnight, but they were in a precarious position in the morning. The ash and tephra layer had grown thick: this may have been a meter or more. Earthquakes were continuous. Climbing out, stones were still falling and they tied pillows to their heads to shield from this! The shore may have been as close as a 100 meters distant. The eruption caused darkness, apart from the lightning flashes, requiring torches. And there he died, whether from exertion or fro the sulphurous air is anyone’s guess. The people he was with survived, and fled further. Only two days later (‘the thirsd day’) had conditions improved enough for them to return and find Pliny the Elder’s body.

The story is full of Roman values: courage and fearlessnes, helpfulness, leadership. Pliny the Elder is presented as a typical Roman hero. After all, this letter was written as an In Memoriam for inclusion in the book of Roman History!

The second letter focusses more on the eruption, albeit seen and experienced from 30 km away.

Pliny the Younger picks up his own story on the first afternoon, but apparently caught no further sight of the eruption cloud. While stones were raining down on his uncle out at sea, he continued studying. The tremors, though, continued and became bad overnight. Those were the same tremors that were felt by the party of his uncle across the Gulf. Sometime, perhaps 4am, it became too bad and he and his other got up. By 6am, they decided to leave as the house was in danger of collapsing from the tremors. The description is vivid: the terrified, fleeing crowd, the ominous black cloud torn by lightning flashes on one side and the retreating sea on the other. By now his uncle lay dying on the distant coast. The retreating sea, by the way, was not the Gulf of Naples which was in the direction of the cloud. It was the sea on the other side of the peninsula. Why was it retreating? It is normally a sign of a tsunami but the letter does not mention this. The sea at Stabiae had been described as ‘rough’. Pyroclastic flows can cause tsunamis even for volcanoes away from the sea: the massive flow across the sea can depress the water and this gives rise to the wave. It happened at Tambora, for instance. Different flows in different places cause interfering waves, made worse by reflections against the coasts. This was possibly the cause of the rough sea. The opposite side of the Misenum peninsula was sheltered from this, but a wave moving into the open sea could have pulled in an out-going current at this coast, lowering the sea here. Of course the water would rise again later, but Pliny did not see this.

Now the black cloud started to descend and ash began to fall, though ‘not a lot at first’. The cloud rolled in off the sea and over the land behind them. His was certainly the outer edge of the collapsing eruption cloud, forming a pyroclastic flow closer to the volcano and a rolling ash cloud here. This cloud was perhaps the reason for the outgoing tsunami wave. Total darkness followed, but Pliny does not mention any heat. And perhaps in this darkness, the sea came back up, unseen. Fleeing people shouted and cried in the sudden night. A strange statement follows on a light that appeared but wasn’t the Sun but approaching fire, presumably from the direction of the eruption. Had the cloud lifted enough for them to catch a glimpse of Vesuvius?

The cloud came back and ash fell like thick snow. Eventually the Sun managed to get through in a haze and the ashfall lessened or stopped. How long this ‘eventually’ took, the story does not say. Based on the fact that the ash fell at perhaps a centimeter per ten minutes (based on them having to stand up every few minutes), one or two hours seems reasonable. It was still morning but their world had changed. Everything was covered by thick ash, even 30 km away from the mountain. The tremors still continued whilst Vesuvius collapsed into a new crater. Herculaneum and Pompei were lost and buried. His uncle lay dead on a sail, one of many victims for whom fortune and bravery had been no match for the power of the eruption. Pliny the Younger was now an adopted son and heir. And volcanology was born.

Albert (the elder), April 2026