Stars appear on their heads during the Argonautic expedition after Orpheus plays his lute, and only one of them dies during their battles with Idas and Lynceus because only one of them is mortal.
Stars appear on their heads during the Argonautic expedition after Orpheus plays his lute, and only one of them dies during their battles with Idas and Lynceus because only one of them is mortal. Born of eggs from Zeus' affair with Leda, one of them manages horses, while the other is a skilled boxer, which explains his name of "many fists". For 10 points, name these twin half-brothers of Helen, whose names also denote the twin stars in the constellation Gemini.
Stars appear on their heads during the Argonautic expedition after Orpheus plays his lute, and only one of them dies during their battles with Idas and Lynceus because only one of them is mortal.
{Castor and Polydeuces} (accept {Pollux} for Polydeuces, and both answers are required)