Castor and Pollux in Wikipedia
(pronounced /ˈkæstər/; Latin: Castōr; Greek: Κάστωρ, Kastōr,
"beaver") and Pollux (/ˈpɒləks/; Latin: Pollūx) or
Polydeuces (/ˌpɒlɨˈdjuːsiːz/; Greek: Πολυδεύκης, Poludeukēs,
"much sweet wine") were twin brothers in Greek and Roman
mythology and collectively known as the Dioskouroi. They
were the sons of Leda by Tyndareus and Zeus respectively,
the brothers of Helen of Troy and Clytemnestra, and the
half-brothers of Timandra, Phoebe, Heracles, and Philonoe.
They are known collectively in Greek as the Dioscuri (/daɪ
ˈɒskjəraɪ/; Latin: Dioscūrī; Greek: Διόσκουροι, Dioskouroi,
"sons of Zeus") and in Latin as the Gemini (/ˈdʒɛmɨnaɪ/;
"twins") or Castores (/ˈkæstəriːz/). They are sometimes also
termed the Tyndaridae or Tyndarids (/tɪnˈdɛrɨdiː/ or /
ˈtɪndərɪdz/; Τυνδαρίδαι, Tundaridai), later seen as a
reference to their father and stepfather Tyndareus.
In the myth the twins shared the same mother but had
different fathers which meant that Pollux was immortal and
Castor was mortal. When Castor died, Pollux asked Zeus to
let him share his own immortality with his twin to keep them
together and they were transformed into the Gemini
constellation. The pair were regarded as the patrons of
sailors, to whom they appeared as St. Elmo's fire...
Read More about Castor and Pollux in Wikipedia