The City of Pompeii Pompeii the ancient city of Italy, found in the Campania Region, built at the mouth of the Sarnus River, it is located about three kilometer south of mount Vesuvius, between Herculaneum and Stabiae. The city was built around 600 b.c. by the Oscans. Which was later taken over by Samnites. It later became a Roman colony in 80 b.c. under the dictator Lucius Cornelius Sulla. Pompeii became a favorite resort for wealthy Romans and reached a population of about 20,000 at the beginning of the Christian era. The city was heavily damaged by earthquakes in a.d. 63 and was later completely demolished in a.d.