The Dioscuri by Giorgio de Chirico. Mid 1950s.
Castor and Polydeuces are the twins sons of Leda of Sparta, the older brothers of Leda’s twin daughters Helen and Clytemnestra. Although “Dioscuri” means “sons of Zeus”, Polydeuces is Zeus’ son, and Castor is the son of Leda’s husband Tyndareus.
The Dioscuri were known for their loyalty to one another, and for their bravery. They were both excellent horsemen, and Polydeuces was famed as a boxer. When Helen was abducted by Theseus, they led a small Spartan force against Athens, captured the city, rescued their sister, and took Theseus’ mother captive, making her Helen’s maid. Castor and Polydeuces participated in the hunt for the Calydonian Boar, and sailed with Jason as Argonauts on the quest for the Golden Fleece.
A long-running feud with their cousins Idas and Lynceus, the sons of Tyndareus’ brother, brought about the end of their mortal lives. Castor had been struck a mortal blow, and Polydeuces begged Zeus to let him die with his twin. Zeus offered Polydeuces the opportunity to share his immortality with his mortal brother, so the two now spend alternate days between Olympus and Hades. Zeus further honored them with the constellation Geminii, which is visible for six months of the year.
The cult of the Dioscuri spread across Greece to Asia Minor and Italy. They have been revered as protectors of travellers, especially horsemen and mariners, and honored with temples and games. According to Roman legend, the Dioscuri were seen fighting on horseback for the Romans at the Battle of Lake Regillus in 496 BCE. Immediately after the battle, they appeared in Rome to announce the victory. A temple was dedicated to them on the Forum in 495 at the place where they were seen to have watered their horses.