The New Student's Reference Work/Castor and Pollux

Cas′tor and Pol′lux, often called Sons of Zeus, were, according to Homeric story, the brothers of Helen of Troy; but another tradition makes them only half-brothers of Helen, their father being Zeus; while still a third account makes only Pollux Zeus’s son, and so he alone was immortal.  Castor was famous for his skill in managing horses; Pollux for his powers in boxing.  Both received divine honors at Sparta as patrons of travelers by sea.  They assisted at the battle (496 B. C.) of Lake Regillus.  Zeus placed the brothers among the stars.  They are the principal stars in the constellation of Gemini or the twins.  Their names are also given to the electric appearance known as St. Elmo’s Fire.