quality:corruption, linguistic:paraphrasing
Prophecy fulfilled

Perseus then returned his magical loans and gave Medusa's head as a votive gift to Athena, who set it on her aegis (which Zeus gave her) as the Gorgoneion. The fulfillment of the oracle was told several ways, each incorporating the mythic theme of exile. In Pausanias he did not return to Argos, but went instead to Larissa, where athletic games were being held. He had just invented the quoit and was making a public display of them when Acrisius, who happened to be visiting, stepped into the trajectory of the quoit and was killed: thus the oracle was fulfilled. This is an unusual variant on the story of such a prophecy, as Acrisius' actions did not, in this variant, cause his death.

In the Bibliotheca, the inevitable occurred by another route: Perseus did return to Argos, but when Acrisius learned of his grandson's approach, mindful of the oracle he went into voluntary exile in Pelasgiotis (Thessaly). There Teutamides, king of Larissa, was holding funeral games for his father. Competing in the discus throw, Perseus' throw veered-and struck Acrisius, killing him instantly. In a third tradition, Acrisius had been driven into exile by his brother Proetus. Perseus petrified the brother with Medusa's head and restored Acrisius to the throne. Then, accused by Acrisius of lying about having slain Medusa, Perseus proves himself by showing Acrisius the Gorgon's head, thus fulfilling the prophecy.

Having killed Acrisius, Perseus, who was next in line for the throne, gave the kingdom to Megapenthes ("great mourning"), son of Proetus, and took over Megapenthes' kingdom of Tiryns. The story is related in Pausanias, who gives as motivation for the swap that Perseus was ashamed to have become king of Argos by inflicting death. In any case, early Greek literature reiterates that manslaughter, even involuntary, requires the exile of the slaughterer, expiation and ritual purification. The exchange might well have proved a creative solution to a difficult problem.