Castor and Pollux were two twins, sons of Zeus. But Castor is killed in a love exploit. Then Pollux, in despair, gets permission from Zeus to live one day in the world of the living and one day in the world of the dead, not to be separated from his brother. “I Dioscuri: Castor and Pollux” in Greek mythology Their mother was Leda, but they had different fathers. Pollux asked Zeus to let him share his own immortality with his twin to keep them together, and they were transformed into the constellation Gemini. The pair were regarded as the patrons of sailors. They were also associated with horsemanship, in keeping with their origin as the Indo-European horse twins.