Poseidon or Posidon (Greek: Ποσειδῶν, gen: Ποσειδῶνος) is one of the twelve Olympian deities of the pantheon in Greek mythology. His main domain is the ocean, and he is called the "God of the Sea". Additionally, he is referred to as "Earth-Shaker" due to his role in causing earthquakes, and has been called the "tamer of horses". He is usually depicted as an older male with curly hair and beard.
The name of the sea-god Nethuns in Etruscan was adopted in Latin for Neptune in Roman mythology; both were sea gods analogous to Poseidon. Linear B tablets show that Poseidon was venerated at Pylos and Thebes in pre-Olympian Bronze Age Greece as a chief deity, but he was integrated into the Olympian gods as the brother of Zeus and Hades. According to some folklore, he was saved by his mother Rhea, who concealed him among a flock of lambs and pretended to have given birth to a colt, which was devoured by Cronos.
There is a Homeric hymn to Poseidon, who was the protector of many Hellenic cities, although he lost the contest for Athens to Athena. According to the references from Plato in his dialogue Timaeus and Critias, the island of Atlantis was the chosen domain of Poseidon.
Cape Sounion (Modern Greek: Aκρωτήριο Σούνιο, transliterated Akrotírio Soúnio, pronounced [akroˈtirʝo ˈsuɲo]; Ancient Greek: Άκρον Σούνιον, Άkron Soúnion; Latin: Sunium promontorium; Venetian: Capo Colonne - "Cape of Columns") is a promontory located 69 kilometres (43 mi) SSE of Athens, at the southernmost tip of the Attica peninsula in Greece.
Cape Sounion is noted as the site of ruins of an ancient Greek temple of Poseidon, the god of the sea in classical mythology. The remains are perched on the headland, surrounded on three sides by the sea. The ruins bear the deeply engraved name of English Romantic poet Lord Byron (1788–1824).