According to the myths Cychreus was the son of the god Poseidon and the nymph Salamis, the daughter of the river-god Asopus. Cychreus became a legendary king of the biggest island in the Saronic Gulf -- Salamis -- and he was worshiped there as a mysterious divine hero. In this mythological story the island was named after Cychreus' mother, the nymph Salamis, but the place was also called "the Snake Island" in relation to the following myth about the king Cychreus. (Originally, the island Salamis took its name from the Phoenician emigrants coming there from Cyprus, for them this place was schalam, "peaceful.")
The ancient authors write that Cychreus was chosen as the king of Salamis after he killed a dangerous snake, which was devastating the island. They also said that Cychreus took care of a small snake, which was similar to the previous destructive serpent. This snake was banished from Salamis by Eurylochus, the friend of Odysseus. The goddess Demeter later took this animal to her sanctuary in Eleusis, located near the island of Salamis (see: Cychreides).
There are different explanations of this story, some of them based on the idea of Apollodorus, who supposed that Cychreus could have been a very cruel king or maybe a killer. Due to this reason he was associated with a snake and therefore was called "the Snake," and his land was known as the Snake Island. In this context there is also an opinion that Cychreus was driven away from Salamis by Eurylochus, and that he found a quite place to live in the sanctuary of Eleusis. Hesiod (in a citation by Strabo) gives us a totally different opinion when he supposed that Cychreus was a serpent-breeder. But according to another, later version, Cychreus was described as a reptile in the parts below his hips, similar to the legendary Athenian king Cecrops.
On the other hand, Cychreus became one of the heroes of the island Salamis. According to the tradition he had his tomb there. The local inhabitants even built the temple of Cychreus where they worshipped him and brought him their offerings. They appealed to him to protect the island in every important historical event. Pausanias also mentioned the story about Cychreus, who was said to have appeared in the image of a serpent at the moment the Athenian fleet was engaged in battle with the Persians near the island of Salamis. The protective power of Cychreus was also commemorated during a controversy between Athens and Megara, two towns which were fighting over the hegemony in Salamis.
Concluding, we can note that the myth about the first legendary king of the island Salamis is related to the myths about the first mythical kings in Attica and their protective and educative role in this region. In the Athenian myth about the kings Cecrops and Erichthonius as well as in the myth about the king Cychreus of Salamis, the snake was a positive symbol associated with a dead hero and implemented his protective power over this land and its inhabitants.