CASTOR AND POLLUX, in Greek and Roman mythology the twin sons of Leda, and brothers of Helen and Clytaemnestra. They were also known as Dioscuri (Gr. "lads of Zeus"), for, according to later tradition, they were the children of Zeus and Leda, whose love the god had won under the form of a swan. In some versions Leda is represented as having brought forth two eggs, from one of which Castor and Pollux were born, from the other Helen. According to another account, Zeus was the father of Pollux and Helen, Tyndareus (king of Sparta) of Castor and Clytaemnestra. In Homer they are said to have been the children of Tyndareus and Leda, and Helen is said to have been the daughter of Leda by Zeus. The Dioscuri were specially rever enced among people of Dorian race, and were said to have reigned at Sparta, where also they were buried. They were the friends of sailors, appearing in the shape of St. Elmo's fire during storms. Later, they were confounded with the Cabeiri (q.v.).