Dioscūri (Dios kouroi, ‘sons of Zeus’), in Greek myth, Castor and Polydeuces (Lat. Pollux). They were native to Sparta, where they were worshipped. In Homer and in Hesiod they are the twin sons Tyndareus and Leda, and the brothers of Helen (of Troy). Later, Polydeuces is represented as the son of Zeus, and immortal. When Castor, the mortal son of Tyndareus, is fatally wounded (see below), Polydeuces chooses to share his immortality with his brother, so that they both spend half their time in the Underworld and the other half with the gods on Mount Olympus. Other accounts make them both sons of Zeus, born like Helen from an egg. They occur in three mythical stories. When Theseus carried off Helen as a child they made an expedition to Attica, recovered her, and took Theseus' mother Aethra as well to be Helen's slave. Helen's place of concealment had been revealed by the hero Akademos (see ACADEMY), whose land was always spared in consequence by invading Lacedaemonians. In another story they took part in the voyage of the Argonauts, Polydeuces distinguishing himself in the fight against Amycus. Finally they carried off the two daughters of a certain Leucippus, Hilaēīra and Phoebē, who were betrothed to their cousins Idas and Lynceus. In the ensuing fight (or, in some versions, in a cattle raid) Castor and both opponents were killed. It was on this occasion that Polydeuces gave Castor a share of his immortality (see above). The Dioscuri are often identified with the constellation Gemini (the Twins). They were commonly regarded as protectors of sailors, to whom they appeared during storms as the lights of St Elmo's fire. They were also notable boxers and horsemen, frequently called ‘riders of white horses’, and therefore the patrons of athletes and athletic contests.
In Roman religion the worship of Castor and Pollux was introduced in early times, Castor always being the more popular. Their temple at Rome (nearly always known as the temple of Castor) was vowed by the dictator Aulus Postumius during the battle of the Romans against the Latins at Lake Regillus (496 BC). The story was that they then fought at the head of the Roman army and after the battle brought the news of the victory to Rome; they were seen watering their horses at the Lacus Iuturnae (‘pool of Juturna’, a fountain in the Forum) and their temple was erected on that spot, beside that of Vesta. According to another story (related in Cicero, De natura deorum), Publius Vatinius (grandfather of the famous tribune) informed the senate that he had met two youths on white horses who told him of the capture of Perseus of Macedon on that day (168 BC); he was thrown into prison until his statement was confirmed by dispatches. The Roman equites regarded the brothers as their particular patrons. The common oaths mecastor and edepol, based on their names, are evidence of their popularity.
