Kastor and Polydeukes

Kastor and Polydeukes (or in Roman; Castor and Pollux, anglicised Kastor/Castor and Polydeuces) are twin brothers that later formed the constellation the Gemini. Their mother was Leda, however Kastor was the mortal son of Tyrandeus and Polydeukes was the demigod son of Zeus. When Zeus seduced Leda in the form of a swan, Leda laid two eggs each producing two offsprings, from one egg was Kastor and Polydeukes and from the another egg was Clytaemnestra and Helen of Troy. Kastor had other sisters by Tyndareus and Leda: Timandra, Phoebe, and Philonoe.