The Greeks, pushed by the narrowness of their ground they founded some colonies along the coasts of Small Asia and the Mediterranean.
The colonies along the coasts of southern Italy as Sibari, Agrigento Velia and Paestum, designate as 'Magna Graecia'.
Toward middle of the 7th century a. C. the city of Sibari, to extend his political and commercial influence on the coast of Tyrrhenian Sea of Southern Italy, founded some of its trading station on the coast of Tyrrhenian Sea.
The most northern was at the mouth of the Sele river and it was made more important by the construction of a sanctuary in honour of Hera. Economic development of Sybarite trade, was the cause the increased power of one of these small centres, that of one was most favoured by its geophysical position. The Greek called this city Poseidonia, later Paistom during the Lucanian period and Paestum in Roman times. At the same time, the Focesans from Asia Minor founded Elea, today Velia. The latter will host the Eleatic school Xenophanes' philosophy and that of physicians, which traces its origins the important Salerno Medical School.
The gradual abandonment from the inhabitants and the overflow of the Salso river (Capodifiume), perhaps joined to a bradisismo, that licked up the city , they contributed to the degradation of the city, and the aqua of the river transformed Paestum in a swamp.
The signs of its slow decline are evident and irreversible during the centuries IV and V, when the inhabited center, was assembled around the ancient Athenaion, then the last inhabitants of Paestum, to escape the malaria (IX century) and to the raids of the Saracens, they were sheltered on the near hills, founding Capaccio Vecchio ( from caput aquaee that is source of the river).
In 1752, king Carlo III of Borbone made to construct to the road towards the South (the actual National 18), crossing the same ancient city, and the temples and the ruins of Paestum were rediscovered.