Founded by the Greeks around 600 B.C.E., it was initially called Poseidonia, from Poseidon, or Neptune, god of the sea, to whom the city had been dedicated. Between 400 and 273 before it was occupied by the Italic population of the Lucanians. In 273 it became a Roman colony with the name of Paestum. But there is no doubt that the foundation of the city was preceded by the installation of a commercial farm on the left bank and near the mouth of the Silaros river and that the malarial conditions of the land then induced the primitive settlers to move the inhabited center towards the east, on a bench calcareous slightly raised on the plain and on the coast, along the course of another minor river (river Salso or Capofiume). From the primitive plant on the Silaros developed the sea and river port of the city and near it arose the Temple of Era Argiva, which soon became one of the largest and most venerated sanctuaries in ancient Italy: about 50 stadiums separated the city from Heraion and the its emporium on the river.The end of the Roman Empire coincided roughly with the end of the city. Towards 500 C.E., in fact, following a malaria epidemic, aggravated by the unhealthiness of the territory, the inhabitants gradually left the city. The rediscovery of Paestum dates back to 1762, when the modern road that still crosses it was built.

The so-called Temple of Neptune (also called the Temple of Poseidon) is the largest temple of the ancient polis of Poseidonia (known with the Roman name of Pæstum), built around the middle of the fifth century BC, the time of greatest flowering in the center [1 ]. It stands in the urban southern sanctuary, just north of the c.d. Basilica, arranged parallel to this. The cell, inside which the image of the titular divinity of the temple was kept, is divided into three naves by two rows of two overlapping orders of seven Doric columns, characterized by an uninterrupted thinning of the stems from the bottom up.

Better known as the Basilica, from the name that the eighteenth-century scholars gave it for the almost total disappearance of the cell walls, the pediment and the entablature. It is actually dedicated to Hera, bride of Zeus and main divinity of Poseidonia. It is a Peripterus with nine columns on the fronts and eighteen on the sides (m. 24.35x54), the cell has well preserved the pronaos, in correspondence with the odd number of columns on the front and is departed from a central colonnade, partly preserved and intended to support the climax of the roof. At the back of the cell is the adyton, an environment inaccessible to the faithful as the seat of the temple treasure. Singular peculiarity, among all the monuments of Doric architecture, offers here and in the temple of Ceres the collar of the capital decorated with pods and sometimes surrounded on the curve of the echinus by a band of lotus flowers and rosettes. In the excavations of 1912 many elements of the clay decoration were collected. The crowning of the temple was in terracotta painted with fake lion-headed eaves and ended with palm-shaped antefixes.