Pompeii, Italian Pompei, preserved ancient Roman city in Campania, Italy, 14 miles (23 km) southeast of Naples, at the southeastern base of Mount Vesuvius. It was built on a spur formed by a prehistoric lava flow to the north of the mouth of the Sarnus (modern Sarno) River. Pompeii was destroyed, together with Herculaneum, Stabiae, Torre Annunziata, and other communities, by the violent eruption of Mount Vesuvius in 79 ce. The circumstances of their destruction preserved their remains as a unique document of Greco-Roman life. Pompeii, Herculaneum, and Torre Annunziata were collectively designated a UNESCO World Heritage site in 1997. Pompeii supported between 10,000 and 20,000 inhabitants at the time of its destruction. The modern town (comune) of Pompei (pop.  25,440) lies to the east and contains the Basilica of Santa Maria del Rosario, a pilgrimage centre.
It seems certain that Pompeii, Herculaneum, and nearby towns were first settled by Oscan-speaking descendants of the Neolithic inhabitants of Campania. Archaeological evidence indicates that the Oscan village of Pompeii, strategically located near the mouth of the Sarnus River, soon came under the influence of the cultured Greeks who had settled across the bay in the 8th century bce. Greek influence was challenged, however, when the Etruscans came into Campania in the 7th century. The Etruscans’ influence remained strong until their sea power was destroyed by King Hieron I of Syracuse in a naval battle off Cumae in 474 bce. A second period of Greek hegemony followed. Then, toward the end of the 5th century, the warlike Samnites, an Italic tribe, conquered Campania, and Pompeii, Herculaneum, and Stabiae became Samnite towns.
Pompeii is first mentioned in history in 310 bce, when, during the Second Samnite War, a Roman fleet landed at the Sarnus port of Pompeii and from there made an unsuccessful attack on the neighbouring city of Nuceria. At the end of the Samnite wars, Campania became a part of the Roman confederation, and the cities became “allies” of Rome. But they were not completely subjugated and Romanized until the time of the Social War. Pompeii joined the Italians in their revolt against Rome in this war and was besieged by the Roman general Lucius Cornelius Sulla in 89 bce. After the war, Pompeii, along with the rest of Italy south of the Po River, received Roman citizenship. However, as a punishment for Pompeii’s part in the war, a colony of Roman veterans was established there under Publius Sulla, the nephew of the Roman general. Latin replaced Oscan as the official language, and the city soon became Romanized in institutions, architecture, and culture.
A riot in the amphitheatre at Pompeii between the Pompeians and the Nucerians, in 59 ce, is reported by the Roman historian Tacitus. An earthquake in 62 ce did great damage in both Pompeii and Herculaneum. The cities had not yet recovered from this catastrophe when final destruction overcame them 17 years later.
Mount Vesuvius erupted on August 24, 79 ce. A vivid eyewitness report is preserved in two letters written by Pliny the Younger to the historian Tacitus, who had inquired about the death of Pliny the Elder, commander of the Roman fleet at Misenum. Pliny the Elder had rushed from Misenum to help the stricken population and to get a close view of the volcanic phenomena, and he died at Stabiae. Site excavations and volcanological studies, notably in the late 20th century, have brought out further details. Just after midday on August 24, fragments of ash, pumice, and other volcanic debris began pouring down on Pompeii, quickly covering the city to a depth of more than 9 feet (3 metres) and causing the roofs of many houses to fall in. Surges of pyroclastic material and heated gas, known as nuées ardentes, reached the city walls on the morning of August 25 and soon asphyxiated those residents who had not been killed by falling debris. Additional pyroclastic flows and rains of ash followed, adding at least another 9 feet of debris and preserving in a pall of ash the bodies of the inhabitants who perished while taking shelter in their houses or trying to escape toward the coast or by the roads leading to Stabiae or Nuceria. Thus Pompeii remained buried under a layer of pumice stones and ash 19 to 23 feet (6 to 7 metres) deep. The city’s sudden burial served to protect it for the next 17 centuries from vandalism, looting, and the destructive effects of climate and weather.
History of excavations
The ruins at Pompeii were first discovered late in the 16th century by the architect Domenico Fontana. Herculaneum was discovered in 1709, and systematic excavation began there in 1738. Work did not begin at Pompeii until 1748, and in 1763 an inscription (“Rei publicae Pompeianorum”) was found that identified the site as Pompeii. The work at these towns in the mid-18th century marked the start of the modern science of archaeology.
Under the patronage of Don Carlos, king of Naples, the military engineer Karl Weber carried out systematic studies from 1750 to 1764, but other early digging was often haphazard and irresponsible, carried out by treasure seekers or other untrained workers. Haphazard digging was brought to a stop in 1860, when the Italian archaeologist Giuseppe Fiorelli became director of the excavations. Areas lying between excavated sites were cleared and carefully documented. Pompeii was divided into nine regions; the insulae (blocks) in each region were numbered, and each door on the street was given a number so that each house could be conveniently located by three numerals. Fiorelli also developed the technique of making casts of bodies by pouring cement into the hollows formed in the volcanic ash where the bodies had disintegrated.
In 1951, after the interruption caused by World War II, intensive excavation was resumed under Amedeo Maiuri, who was in charge of the excavations from 1924 to 1961. Large areas were uncovered to the south of the Via dell’Abbondanza, in Regions I and II, and the debris piled outside the city walls was cleared away. This revealed the Porta (Gate) di Nocera and an impressive stretch of cemetery lining each side of the road leading from the gate to Nuceria. By the 1990s, about two-thirds of the city had been excavated.
In the vicinity of Stabiae and Gragnano, excavations initiated by Don Carlos of Naples discovered 12 villas between 1749 and 1782. Work was resumed there in the 20th century. The Villa of San Marco, with its two large peristyle gardens and bath, is the best preserved. Other villas have been found at nearby Scafati, Domicella, Torre Annunziata, and on the lower slopes of Vesuvius near Boscoreale and Boscotrecase. Many of these villas were reburied after excavation, but a few can be seen, notably the Villa of the Mysteries.