Caroline Alexander at Lapham's Quarterly:
The Gorgon is evoked in a variety of literature and above all in art. Images of the Gorgon head, or Gorgoneion, appear from the seventh century BC onward on painted vases, as architectural features, and on coins. In mythology, the Gorgons were three sisters, Stheno, Euryale, and Medusa. Along with other monstrous offspring that included Echidna (Viper) and Ophis (Serpent), the Gorgons were the result of an incestuous union between children of Pontos (Sea) and Gaia (Earth). The source for this genealogy is the Greek poet Hesiod, whose Theogony, written in the seventh century BC, is the basis of much mythological knowledge. For reasons Hesiod does not explore, the first two Gorgons were divine, while Medusa was wholly mortal. Other early poets add further details: the Gorgons lived in the far west, toward the edge of night, on a rocky island beyond the streams of all-encircling Ocean. Little is given in the way of physical description except to note that they wore snakes wrapped about their waists, and that the face of Medusa turned men to stone.
It is the story of Medusa’s head, however, that rivets attention. Central to this story is the hero Perseus, a prince of Argos, an actual city of great antiquity that once commanded much of the Peloponnese; his association with other named cities of the Argolid, such as Mycenae and Tiryns, has led some to believe there may have been a historical king behind the myth. In mythology, Perseus is the son of beautiful Danaë, whose own father locked her away in a bronze chamber in order to outwit a prophecy that any son she bore would kill him. Zeus, however, assuming the form of a shower of golden light, infiltrated the chamber and impregnated her. When Danaë gave birth to Perseus, her father put mother and child into a chest and set them adrift upon the sea. An island fisherman of noble blood rescued them, and they remained with their savior on the island. When Perseus came of age, he was invited to a birthday celebration at the court of the local king, who happened to be the fisherman’s brother. Asked what gift he would bring for the occasion, Perseus replied, rashly and inexplicably, “the Gorgon’s head.” When the king held him to his answer, Perseus’ adventures began.