Hamilton compares this story, which was very popular in Greece, with a fairy tale. She takes the complete tale mostly from Apollodorus, though many poets allude to it. King Acrisius of Argos learns from the Oracle at Delphi that his daughter, Danaë, will give birth to a son that will kill him. Acrisius fears that the gods will punish him if he kills his daughter, so he imprisons Danaë to keep her from getting pregnant.
This story returns to the idea of fate and the use of a prophecy as a plot point. This is also another example of someone being afraid to break a sacred rule (like a father killing his daughter) and so going about their goal in a roundabout way, which always fails.
Danaë lives as a prisoner underground, but one day Zeus comes to her as a golden rain falling through her air chute, and he magically impregnates her. Danaë gives birth to Perseus. When Acrisius discovers the child and who its father was, he puts Danaë and Perseus in a wooden chest and throws it out to sea.
This is a typical example of a mortal trying to avoid his fate and failing, but it is less ironic and poignant than most, as Acrisius appears only briefly in the tale much later. His hubris in trying to avoid the prophecy simply sets the stage for Perseus.
Danaë and Perseus drift around and eventually are found by Dictys, a kind fisherman, who takes them in. Dictys’s brother Polydectes is the wicked ruler of the island where they live, and Polydectes falls in love with Danaë. Polydectes wants to get rid of Perseus and marry Danaë, so he manages to convince Perseus to kill Medusa, the Gorgon, and bring her head as a wedding gift.
Like many other kings in the myths, Polydectes fears to kill Perseus outright, as Perseus has been his guest, so instead he sends him on a deadly quest. Like with Jason, the first sign of Perseus’s “hero” status (besides being raised without a father) is that he gladly accepts impossible, dangerous tasks.
Medusa is a woman with impenetrable scales and snakes for hair, and anyone who looks at her turns to stone – killing her should be an impossible feat. But the gods help Perseus, and Hermes appears to him and gives him a magical sword, and Athena gives him a mirrored shield. Perseus then travels to the Graiae (the three Gray sisters who share only one eye), and he steals their eye until they tell him how to find the Hyperborean nymphs.
Similarly to Jason, Perseus’s “heroism” mostly involves being helped by others, in this case Hermes and Athena. Hamilton points out that the story becomes like a “fairy tale” with its collection of magical objects that help the hero. Perseus’s cleverness in dealing with the Graiae is his only original idea in the story.
Perseus travels to the Hyperboreans with Hermes, and the nymphs give him winged sandals so he can fly, a magical wallet that can hold anything, and a cap that makes him invisible. Fully equipped now, Perseus flies to the island of the Gorgons.
Perseus’s success as a hero depends mostly on the magical objects given to him and the exact instructions he receives.
The Gorgons are asleep, and Perseus creeps up on them, looking at them only in the reflection of Athena’s mirrored shield so he is not turned to stone. Athena and Hermes accompany him, and they point out which one is Medusa – this is important, as her two sisters are immortal. Perseus chops off the sleeping Medusa’s head, puts it in his magic wallet, and flies away.
The actual great deed – the killing of Medusa – seems almost unfair when it is actually described. Medusa is sleeping and Perseus is invisible, so she stands no chance against him.
On his way home, Perseus comes upon Andromeda, a beautiful princess who has been chained to a rock and is about to be eaten by a sea serpent – all as a punishment for her mother, Cassiopeia, who had offended the gods by boasting of her own beauty.
This is yet another example of the gods punishing a mortal for hubris, but their justice not falling on the actual sinner herself, but on her daughter. It is also another implication of human sacrifice.
When the sea serpent appears, Perseus cuts off its head. He frees Andromeda, takes her to her home, and marries her. Perseus then returns to his own island to find that Polydectes, enraged at Danaë’s refusal to marry him, has driven Danaë and Dictys to hide in a temple.
Perseus fulfills another motif of the hero’s quest, as he marries a princess after successfully slaying a monster. His “heroism” is very simplistic and straightforward, and not as interesting to modern readers.
Perseus goes to Polydectes’ palace, where the King is having a banquet with all his followers. Perseus enters the banquet hall and holds up Medusa’s head, turning everyone (except himself) to stone. He then makes Dictys king of the island, and he, Andromeda, and Danaë return to Greece. Perseus unwittingly fulfills the oracle’s prophecy there, as he accidentally kills his grandfather Acrisius (who is disguised as a spectator) in a discus-throwing contest. Perseus and Andromeda then live happily ever after.
This is the final motif of the hero’s quest – returning home, killing the usurpers, and reclaiming his rightful position. The fulfillment of Acrisius’s fate is almost an afterthought of the story, and is not exploited to its full drama and irony like it will be in later, more complex tales. Like Hyacinthus, Acrisius is another victim of a discus accident.