Pollux

Pollux is the immortal son of Zeus and Leda, twin of Castor and one of the Dioscuri. His Greek name is Polydeuces; Pollux is the Latin form.

Zeus came to Leda as a swan, and that same night she lay with her husband, Tyndareus. In the usual version, told by Apollodorus, Pollux and Helen were Zeus's children and Castor and Clytemnestra those of Tyndareus. Euripides has Helen born from an egg, and Horace has the twins share one; many retellings give Leda two eggs, Pollux hatching with Helen and Castor with Clytemnestra.

The brothers joined Meleager's hunt for the Calydonian boar and sailed with Jason on the Argo. Amycus, king of the Bebryces, made every stranger box with him; in Apollonius's Argonautica, Pollux kills him with a blow above the ear, while in Theocritus he spares him once the king swears to leave strangers in peace. When Theseus and Pirithous carried off the young Helen, the twins invaded Attica, recovered her at Aphidnae and took Theseus's mother, Aethra, captive.

Their last fight was against Idas and Lynceus, sons of Aphareus. Pindar traces it to a quarrel over cattle; later authors, to the daughters of Leucippus, whom the twins had carried off. Lynceus, the sharpest-eyed of men, spotted the twins hiding in a hollow oak, and Idas speared Castor. Pollux killed Lynceus, and Zeus blasted Idas with a thunderbolt.

In Pindar's tenth Nemean ode, Pollux begs to die with his brother, and Zeus offers a choice: to live forever on Olympus, or to share Castor's lot, half the time beneath the earth and half in the golden halls of heaven. Pollux chooses his brother, so the twins spend one day beside Zeus and the next under the earth at Therapne, near Sparta.

Set among the stars as Gemini, whose two brightest stars bear their names, they also protected sailors: the Homeric Hymn to the Dioscuri shows them swooping down to calm the sea, and the lights on mastheads in storms, later called St. Elmo's fire, were taken as their sign. Pollux was the patron of boxers, Castor of horsemen.