In Greek mythology, Melicertes, later called Palaemon or Palaimon, was a Boeotian prince as the son of King Athamas and Ino, daughter of King Cadmus of Thebes. He was the brother of Learchus.
Sculpture in the Park of Versailles depicting Ino and Melicertes
''The Insane Athamas Killing Learchus, While Ino and Melicertor Jump into the Sea'' by Wilhelm Janson (Holland, Amsterdam), Antonio Tempesta (Italy, Florence, 1555–1630) at Los Angeles County Museum of Art, Los Angeles
Silver plate with relief of Ino, Melicertes and an ichthyocentaur, ca. 590-650 AD, Benaki Museum.
Portunus was the ancient Roman god of keys, doors, livestock and ports. He may have originally protected the warehouses where grain was stored, but later became associated with ports, perhaps because
Melicertes
…Euripides' Iphigeneia in Tauris, where he is already the "guardian of ships". The paramount identification in the Latin poets of the Augustan age is with Portunus, the Roman god of safe harbours, memorably in Virgil's Georgics. Ovid twice told the story of Ino's sea-plunge with Melicertes in her arms. Ovid's…
Temple of Portunus in the Forum Boarium
Roman key Pan face 1st century CE
Bas relief from Arch of Marcus Aurelius showing sacrifice
Roman key with Janus-style handle 1st century CE