Pausanias, describing the temple of Poseidon, allotted the oracle at Delphi and the island of Delos to Apollo, exchanging them with Tainaros cape and the island of Kalavria. Spheros, the son of Hermes helped Pelopas to win the king of Pissas, Hinomao, in the chariot race, and marry his daughter Hipodamia.

It is said that Pelopas killed him after the victory or he killed him when he attempted to kiss Hipodamia or still, that he killed him because Hipodamia fell in love with him and when he rejected her, she said to Pelopas that he raped her. As for the neighboring Troizina, he mentions that the matricide Orestes arrived there to be purified for his murders. According to a legend, when Theseus was seven years old, Pitheas welcomed Hercules in his palace. Although the other children run away when they saw the lion's hide, Theseus was armed with an axe, supposing that it was a real lion.

There are two versions, about the death of Ippolytos according to Pausanias: either Ippolytos was killed when Poseidon turned over his chariot but Aesculapius resurrected him or that he was ascended into the sky and became the known asterism. The cape Skileo is said to have taken its name from the mythological princess Skila. The daughter killed her father by cutting his magic purple hair for the sake of the king of Crete, Minos.

There was a limited presence of Dryopes in Poros during the end of post-Helladic era, in the area where later the town around Poseidon's temple was developed. The powerful Mycenaean nautical station of the area was the steep rocky island Modi or Liontari (= lion) to the eastern coast of Poros. The people of Troizina took part in the Trojan War. Kalavria, until the Archaic era, was under the domination of Troizina. In the middle of the 7thcentury BC, the amphictyony of Kalavria appeared, with Poseidon's temple as a seat, which preexisted in Poros since the end of 8thcentury BC. It was a nautical, religious and political confederation with members the cities of Athens, Aegina, Epidaurus, Nafplia, Prassia and Orchomenos; they all joined forces to protect their independence and trade from the Argives. In the beginning of 5th century BC, the Persian fleet sailed in the Aegean Sea.

The spring of 480 BC, the Persians attempted to attack Greece for a second time. When the two most powerful cities, Athens and Sparta decided to overcome each other, the dreadful Peloponnesian War broke out which expanded to the area of Argosaronic gulf. When, in the middle of 4thcentury BC, the Macedonians appeared in the Greek area, the Greek cities reacted and Troizina offered refuge to Athinogenis, an anti-Macedonian who became the tyrant of the region. In the summer of 323 BC, when Alexander he died, he returned triumphantly in Athens. The following year the Athenians were beaten by Macedonians in the Lamia War and Demosthenes sought refuge in the temple of Poseidon. Pausanias, according to the letters which were sent by the Macedonian Commander in Rhodes in which he mentions by name all those who had been bribed by Arpalos, he questions Demosthenes's guilt whose name is not mentioned despite being a fanatic anti-Macedonian.

However, Poros played an important role during the Independence War because, since it is located near the Peloponnese, it became a passage and a place of meeting of several personalities of that time, despite the fact that in the opposite coast there was a Turkish guard. In 1828, the deployments of the first Greek navy yard were formed and remained there until 1878.

In September of the same year, the ambassadors of the three powers gathered in Poros for the meeting with Kapodistrias to discuss the definition of the borders of the New Greek state. On July 1831, tragic events took place in the port of Poros by the naval battle fighters who had previously won glory for the national fleet. Poros was also a source of inspiration for many great artists of our century, Greeks and foreigners.