Castor and Pollux, often called Dioscuri or "sons of Zeus," were according to Homer the sons of Leda and Tyndareus, and so brothers of Helen of Troy. Another tradition made both of them sons of Zeus and Leda; a third made only Pollux Zeus's son, and so alone 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 the Romans at the battle of Lake Regillus. One story tells that when Castor, the mortal, was killed, Pollux prayed Zeus to let him die with him, and was permitted either to live as his immortal son in Olympus, or to share his brother's fate and live one day in heaven with the gods, the other among the shades. Zeus placed the brothers among the stars as Gemini, and their names are attached to the brightest stars in that constellation.