The twin brother of Castor, the twin sons of Zeus by Leda; great, the former in horsemanship, and the latter in boxing; famed for their mutual affection, so that when the former was slain the latter begged to be allowed to die with him, whereupon it was agreed they should spend a day in Hades time about; were raised eventually to become stars in the sky, the Gemini, twin signs in the zodiac, rising and setting together; this name is also given to the electric phenomenon called St. Elmo's Fire.