Leda and the Swan (Peter Paul Rubens) either Zeus or Tyndareus, each man is said to be the father of all four children. Castor and Pollux were called the Dioscuri meaning “Zeus’s sons,” even though Castor was mortal because he was the son of Tyndareus and Pollux was immortal because he was the son of Zeus. According to Hermes in Lucians’ "The Dialogues of the Dead", Leda and her daughter (Helen of Troy) are the only women worthy of the title “beauties of old.” Rubens’s depictions of Leda clearly embody the phrase. With Leda’s curvy figure, alabaster skin, and golden hair, she is a sight to behold.
Castor et Pollux to remain alive with her for a single day. Telaira bitterly accuses him of never having loved her. Jupiter descends in a storm as a deus ex machina to resolve the dilemma. He declares that Castor and Pollux can both share immortality. The opera ends with the "fête de l'univers" ("Festival of the Universe") in which the stars, planets and sun celebrate the god's decision and the twin brothers are received into the Zodiac as the constellation of Gemini. The prologue was completely cut; it was no longer politically relevant and the fashion for operas having prologues had died out.