Castor and Pollux Castor and Pollux Castor and Pollux (or in Greek, Polydeuces) were twin half-brothers in Greek and Roman mythology, known together as the Dioscuri. Their mother was Leda, but they had different fathers; Castor was the mortal son of Tyndareus, the king of Sparta, while Pollux was the divine son of Zeus, who seduced Leda in the guise of a swan. Though accounts of their birth are varied, they are sometimes said to have been born from an egg, along with their twin sisters Helen of Troy and Clytemnestra. In Latin the twins are also known as the Gemini (literally "twins")
Bayer designation magnitude (those between magnitudes 1.51 and 2.5), labeling them from "gamma" through "zeta" in "top-down" (north-to-south) order. The "First to Rise in the East" order is used in a number of instances. Castor and Pollux of Gemini may be an example of this: Pollux is brighter than Castor, but the latter rises earlier and was assigned "alpha". In this case, Bayer may also have been influenced by the traditional order of the mythological names "Castor and Pollux": Castor is generally named first whenever the twins are mentioned. Although the brightest star in Draco is Eltanin (Gamma Draconis), Thuban was assigned