Castor was the son of Leda and Tyndareus, Pollux the son of Leda and Zeus.
They were great warriors and were noted for their devotion to each other.
In one version of the legend, after Castor was killed by Lynceus, Pollux, in accordance with the classical tradition that one of every set of twins is the son of a god and thus immortal, begged Zeus to allow his brother to share his immortality with him.
Zeus arranged for the twins to divide their time evenly between Hades and Heaven,
and in their honor he created the constellation Gemini.
