Dioscuri
DIOSCURI dī ŏs ku’ re (Διόσκουροι, G1483, sons of Zeus). The twin patrons of distressed seamen in Gr. and Rom. mythology, whose names were Castor and Pollux.
Traditionally the sons of Zeus by Leda, to whom he appeared as a swan, they were also considered to be the children of Tyndareus, king of Sparta, where they were said to have ruled and had been buried. They were esp. worshiped by the Dorian Greeks. Castor was a great charioteer and Pollux a boxer. When Pollux was offered immortality by Zeus, he chose to share death with Castor who had been killed in a fight.
As the patrons of sailors, they were identified with the two highest stars of the constellation Gemini (Twins) and appeared also to sailors during electrical storms as St. Elmo’s fire.
Paul sailed from Malta to Puteoli on an Alexandrian ship which was marked by the Dioscouri (Acts 28:11). The RSV interprets this to mean “with the Twin Brothers as figurehead.” It was prob. the name of the ship which carried a symbol of the gods on the masthead, or as the figurehead.
International Standard Bible Encyclopedia (1915)
(Dioscouroi; in Ac 28:11, the King James Version Castor and Pollux, the Revised Version (British and American) thE TWIN BROTHERS; in margin, "Dioscuri"): The sign of the ship on which Paul sailed from Melita to Syracuse and Rhegium. The Dioscuri (i.e. sons of Zeus), Castor and Pollux, are the two chief stars in the constellation of the Twins. Some 4,000 years BC they served as pointers to mark the beginning of the new year by setting together with the first new moon of springtime. The constellation of the Twins was supposed to be especially favorable to sailors, hence, ships were often placed under the protection of the twin gods.