In the summer of AD 79, A Roman fleet rested in the docks of an Italian town called Misenum, on the western horn of the Bay of Naples, about 150 miles south of Rome. In one of its lavish seaside villas, Pliny, the fat, rich commander of the naval detachment who had also achieved some fame as a philosopher, laid on a blanket in the yard, writing his latest work. A sizable staff attended to his wishes, answering every command he instituted.

Pliny's sister Plinia, who shared the villa with him, appeared and drew his attention to an oddly shaped cloud coming from inland. Pliny called for his shoes and moved to a place where he could better see what was happening. From his vantage point, he saw a vertical column of gray and white, rising straight up toward the sky; once it reached a certain height, the hazy cloud spread out to the side, giving the impression of a pine tree's umbrella canopy. Pliny, being a prolific writer of nature, most likely recognized it as a volcanic eruption, although he could not tell at first from which peak the cloud rose. On that morning, Pliny stood on his patio, observing the first stage of the colossal eruption of Mount Vesuvius.

Pliny, deciding that the event required further investigation, readied a ship to allow him a view from the sea. He offered to bring Plinia's 17-year-old son with him, but the boy, unimpressed by the phenomenon, preferred to remain in the villa, and his mother refused to leave her child. As Pliny therefore headed toward his small, fast cutter, a messenger delivered an urgent letter from Rectina, the wife of one of his friends, pleading for assistance; their house was in a town at the foot of the erupting volcano, and they had no means of escape except by sea.

Grasping the scope of the danger, Pliny changed his orders and commanded several larger galleys to accompany him into the the heart of the Bay of Naples to evacuate as many as possible from the coastal villages of Pompeii and Stabia. On his way in, Pliny noted that the cloud he had first seen owed its gray and white coloring to the fact that it was comprised of rocks, ash, and pumice projected violently into the air; now, with some time having passed, that cloud of debris was raining down on the bay, the ships, and the coastal towns, pelting the inhabitants and making passage difficult, even by sea.

Painstakingly noting the natural effects in his journal, Pliny commanded his ships into the heart of the bay, even as numerous other Pompeiian and Stabian ships frantically fled the volcano. His helmsman, concerned about the danger, advised Pliny to flee, to which the commander replied, "Fortes fortuna iuvat", translating to "Fortune favors the brave", and the fleet landed in Stabia, at the home of another of Pliny's friends, Pomponianus.

The visibly upset Pomponianus greeted his friend as both parties were being pelted with falling pieces of rock, which by this point covered the ground. Pliny, in an attempt to calm his friend by displaying his own composure, ordered his servants to carry him into the bathroom for some relaxation time. He projected a relaxed and happy demeanor, repeatedly telling Pomponianus and his staff that there was nothing to fear; the fires on the side of the mountain were probably abandoned peasant bonfires, or burning houses left unattended. Even as the home continued to be pelted by the falling stones and ash, Pliny cheerfully ate, and then took a nap, the depth of his sleep confirmed by the servants outside the room who could hear the corpulent commander snoring heavily.

Eventually the rocks and debris gathering outside piled up so high that they threatened to seal the house in. Pomponianus awoke Pliny, informing him of this development and telling him they must make a decision soon. The group agreed to abandon Pomponianus's villa and escape across the sea while they could; they all tied pillows to their heads to protect themselves from the falling objects and, although Pliny had slept through the night and the sun had risen, the volcanic cloud had blocked out the sun almost completely, so they lit torches so they could see. The party hurried down to the water's edge, but Pliny quickly realized that the choppy, disturbed water was too difficult to navigate, so he called for his servants again to set down a blanket. The heavyset man then laid down on it for a rest, exhausted by the travel and exhibiting increasingly severe breathing difficulties, and called for some cold water to drink.

The initial, ash- and pumice-spewing phase of the eruption of Pompeii, now known now to vulcanologists as the Plinian phase, soon drew to an end, and the parties of Pliny and his friend Pomponianus could sense the change. Fires drew nearer to Stabia, and the air reeked strongly of sulfur. Many of the people cried out to the gods for assistance, and others lamented that the gods were all dead and the world was coming to a fiery end. Pliny's assistants informed him that it was time to go, and the big man struggled to get to his feet. Despite being supported by two of his slaves, he could barely stand, and almost immediately collapsed to the ground. The rest of the party, fearing for their own lives, fled.

Not long thereafter, Vesuvius exploded into two pyroclastic clouds, asphyxiating anyone (probably including Rectina) left in the towns of Oplontis, Herculaneum, and Pompeii, burying the latter in over nine feet of dust, rocks, and debris. Pomponianus and his party managed to escape the eruption, catching up with Plinia and her son before fleeing the area. Pliny the Elder's body was discovered two days later, in the ash-buried ruins of Pomponianus's villa; chroniclers reported that he choked on the volcanic fumes, but as no one else in his party was affected, it is likely that he instead died of a heart attack or another weight or fitness-related malady exasperated by the choking atmosphere.

Plinia's teenage son, Gaius Plinius Cecilius Secundus, later became known as Pliny the Younger; years later, after reaching the esteemed position of Roman Consul, he interviewed the survivors and chronicled the incident in a series of letters to the historian Tactitus. Vesuvius last erupted in 1948, and is today a national park. Any seismographic activity is vigilantly monitored by the nearby Osservatorio Vesuvio, and there are numerous plans to evacuate the 600,000 or so people in its shadow.

Links and Sources:
The letter from Pliny the Younger to Tactius is online here.
Painting of Pompeiians fleeing Vesuvius is by Peter Bianchi, from National Geographic.
The map of the area around Vesuvius is from NASA.