Strabo describes the coastwise journey along the Hermionic Gulf: On Calauria a Doric temple of Poseidon was built in the ancient sanctuary, possibly around 520 BCE.

There is strong evidence that the epithet of Poseidon at Kalaureia was Geraistos (Γεραιστός), a word from an unknown pre-Hellenic language.

[2] A 6th century A.D. dictionary by Stephanus of Byzantium gives the names of Zeus's sons as Geraistos, Tainaros, and Kalauros, who sailed from an unspecified location and landed in different places on the Peloponnesus.

[7] Pausanias and Strabo both quote the following oracle: "For thee it is the same thing to possess Delos or Kalaureia / most holy Pytho [Delphi] or windy Taenarum."

[10] A peribolos (περίβολος) wall enclosing the sanctuary site was built with the temple,[11] but there are no earlier traces of structures.

However, there is no archaeological evidence to corroborate this list, and modern scholars believe that a feast in the ancient temenos celebrating the "revival" of the amphictyony, may have been based on a Hellenistic invention; the feast certainly existed: a third-century BCE plaque celebrating the "revival" of the Kalaureian League has been recovered.

[18] Excavations were resumed in 1997, conducted by the Swedish Institute in Athens in collaboration with the Greek National Heritage Board.

In 2007-2012 the extensive research program "The City, the God, and the Sea" was financed by Riksbankens Jubileumsfond, and a final report of the results, written in Swedish, is available with open access at rj.se.

Little is known about the temple constructed during this period as it was almost completely robbed out by the time of the early Swedish excavations and when modern work started only foundation trenches and roof tiles remained.

More is known of Stoa A which originally was a Doric building with polygonal walls covered in red plaster and with an inner Ionic colonnade.

The proximity to the sanctuary suggests that the temenos of Poseidon was surrounded by the city at this time and not isolated from the urban landscape.