Leda (mythology) and by him, mother of Helen of Troy, Clytemnestra, and Castor and Pollux (also spelled "Castor and Polydeuces"). Leda also had other daughters by Tyndareus: Timandra, Phoebe, and Philonoe. Leda was admired by Zeus, who seduced her in the guise of a swan. As a swan, Zeus fell into her arms for protection from a pursuing eagle. Their consummation, on the same night as Leda lay with her husband Tyndareus, resulted in two eggs from which hatched Helen (later known as the beautiful "Helen of Troy"), Clytemnestra, and Castor and Pollux (also known as the Dioscuri). Which children are the
Castor and Pollux a blow from his spear—but not before Castor called out to warn Pollux. In the ensuing brawl, Pollux killed Lynceus. As Idas was about to kill Pollux, Zeus, who had been watching from Mt. Olympus, hurled a thunderbolt, killing Idas and saving his son. Returning to the dying Castor, Pollux was given the choice by Zeus of spending all his time on Mount Olympus or giving half his immortality to his mortal brother. He opted for the latter, enabling the twins to alternate between Olympus and Hades. The brothers became the two brightest stars in the constellation Gemini ("the twins"):