Founded around the end of the 7th century BC by colonists from the Greek city of Sybaris, and originally known as Poseidonia, it later became the Roman city of Paestum in 273 BC after the Graeco-Italian Poseidonians sided with the loser, Pyrrhus, in war against Rome during the first quarter of the third century BC.
The city continued to prosper during the Roman imperial period, but started to go into decline between the 4th and 7th centuries. It was abandoned during the Middle Ages and its ruins only came to notice again in the 18th century, following the rediscovery of the Roman cities of Pompeii and Herculaneum. The decline and desertion were probably due to changes in local land drainage patterns, leading to swampy malarial conditions.
On September 9, 1943, Paestum was the location of the landing beaches of the U.S. 36th Infantry Division during the Allied invasion of Italy. German forces resisted the landings from the outset, causing heavy fighting within and around the town. Combat persisted around the town for nine days before the Germans withdrew to the north.
The city of Paestum covers an area of approximately 120 hectares, but only 25 hectares have been excavated: the standing remains of three major temples in Doric style, dating from the first half of the 6th century BC and dedicated to Hera and Athena (although they have traditionally been identified as a basilica and temples of Neptune and Ceres, owing to 18th-century mis-attribution) and the Roman Forum, thought to have been built on the site of the preceding Greek agora; on the north side of the forum is a small Roman temple, dated to around 200 BC and dedicated to the Capitoline Triad, Jupiter, Juno and Minerva; to the north-west of the forum is the amphitheater where you can see only the southern half (the northern is buried under a road).
Close to the archaeological area is the museum, which houses an important collection of ancient Greek objects and Paestum in southern Italy, primarily the funeral from the cemeteries of Greeks and Lucanians: vases, weapons and paintings. The most important paintings, which interpret the transition from life to the dead, like a diver jumping into the water, come from the famous Tomb of the Diver (480-470 BC) and are the only examples of classical Greek art and Magna Graecia.