Pliny had received from Emperor Vespasian, who had died two months earlier, the appointment of praefectus classis (fleet commander) in the Roman Navy.
He was stationed at Misenum, at the time of the great eruption of Mount Vesuvius, which destroyed and  buried Pompeii and Herculaneum.
He was preparing to cross the Bay of Naples to observe the phenomenon directly when a message  arrived from  his friend Rectina asking to rescue Pomponianus and her.
Launching the galleys under his command to the evacuation of the opposite shore, he himself took "a fast-sailing cutter", a decision that may have cost him his life.
His nephew, Pliny the Younger, provided an account of his death, obtained from the survivors.
The nephew and his mother had decided not to go on the voyage across the bay.

As the light vessel approached the shore near Herculaneum, cinders and pumice began to fall on it.
Pliny's helmsman advised turning back, to which Pliny replied, "Fortune favours the brave; steer to where Pomponianus is." (
Stabiae, near the modern town of Castellammare di Stabia.)
They landed and found Pomponianus "in the greatest consternation."
Pliny hugged and comforted him.
They could not find Rectina.
They loaded the cutter, but the same winds that brought it to Stabiae prevented it from leaving.
Pliny reassured his party by feasting, bathing, and sleeping while waiting for the wind to abate, but finally they had to leave the buildings for fear of collapse and try their luck in the pumice fall.
Pliny sat down and could not get up even with assistance, and was left behind.
His companions theorized that he collapsed and died through inhaling poisonous gases emitted from the volcano.
On their return two days later after the plume had dispersed, his body was found under the pumice with no apparent external injuries.
The problem with the toxicity theory is that his companions were unaffected by the same fumes, and they had no mobility problems, whereas Pliny had to sit and could not rise.
As he is described as a corpulent man, who also suffered from asthma,  his friends are thought to have left him because he was already dead.

The story of his last hours is told in a letter addressed 27 years afterwards to Tacitus by  Pliny the Younger, who also sent to another correspondent, Baebius Macer, an account of his uncle's writings and his manner of life.
The fragment from Suetonius (see under "External links" below) states a somewhat less flattering view, that Pliny approached the shore only from scientific interest and then asked a slave to kill him to avoid heat from the volcano.
It is not as credible a source, as it is clear from the nephew's letter that the persons Pliny came to rescue escaped to tell the tale in detail.
Moreover, Suetonius hypothesizes that a party witnessing events so agonizing as to destroy Pliny or cause him to order his own death are suspect as they apparently were subject to none of these fatal events themselves.

In 1859, Jacob Bigelow, M.D., after summarizing the widespread misinformation about Pliny's death, examined the evidence and concluded that Pliny was overweight, in poor health, and died of a heart attack.
 In 1967, science historian Conway Zirkle similarly stated that "there is widespread and persisting misinformation" about Pliny's death.
He suggested that despite his rescue attempt, Pliny never came within miles of Vesuvius and no evidence has been found that shows he died from breathing in fumes, and like Bigelow, concluded that he died of a heart attack.
Pliny had received from Emperor Vespasian, who had died two months earlier, the appointment of praefectus classis (fleet commander) in the Roman Navy. He was stationed at Misenum, at the time of the great eruption of Mount Vesuvius, which destroyed and  buried Pompeii and Herculaneum. He was preparing to cross the Bay of Naples to observe the phenomenon directly when a message  arrived from  his friend Rectina asking to rescue Pomponianus and her. Launching the galleys under his command to the evacuation of the opposite shore, he himself took "a fast-sailing cutter", a decision that may have cost him his life. His nephew, Pliny the Younger, provided an account of his death, obtained from the survivors. The nephew and his mother had decided not to go on the voyage across the bay.
As the light vessel approached the shore near Herculaneum, cinders and pumice began to fall on it. Pliny's helmsman advised turning back, to which Pliny replied, "Fortune favours the brave; steer to where Pomponianus is." (Stabiae, near the modern town of Castellammare di Stabia.) They landed and found Pomponianus "in the greatest consternation." Pliny hugged and comforted him. They could not find Rectina. They loaded the cutter, but the same winds that brought it to Stabiae prevented it from leaving. Pliny reassured his party by feasting, bathing, and sleeping while waiting for the wind to abate, but finally they had to leave the buildings for fear of collapse and try their luck in the pumice fall. Pliny sat down and could not get up even with assistance, and was left behind. His companions theorized that he collapsed and died through inhaling poisonous gases emitted from the volcano. On their return two days later after the plume had dispersed, his body was found under the pumice with no apparent external injuries. The problem with the toxicity theory is that his companions were unaffected by the same fumes, and they had no mobility problems, whereas Pliny had to sit and could not rise. As he is described as a corpulent man, who also suffered from asthma,  his friends are thought to have left him because he was already dead.
The story of his last hours is told in a letter addressed 27 years afterwards to Tacitus by  Pliny the Younger, who also sent to another correspondent, Baebius Macer, an account of his uncle's writings and his manner of life. The fragment from Suetonius (see under "External links" below) states a somewhat less flattering view, that Pliny approached the shore only from scientific interest and then asked a slave to kill him to avoid heat from the volcano. It is not as credible a source, as it is clear from the nephew's letter that the persons Pliny came to rescue escaped to tell the tale in detail. Moreover, Suetonius hypothesizes that a party witnessing events so agonizing as to destroy Pliny or cause him to order his own death are suspect as they apparently were subject to none of these fatal events themselves.
In 1859, Jacob Bigelow, M.D., after summarizing the widespread misinformation about Pliny's death, examined the evidence and concluded that Pliny was overweight, in poor health, and died of a heart attack.  In 1967, science historian Conway Zirkle similarly stated that "there is widespread and persisting misinformation" about Pliny's death. He suggested that despite his rescue attempt, Pliny never came within miles of Vesuvius and no evidence has been found that shows he died from breathing in fumes, and like Bigelow, concluded that he died of a heart attack.
Pliny the Elder