In Greek mythology, Cayster, also Causter or Caystrus (), is a river god, deification of the river by the same name flowing in Lydia and Ionia (now called Küçük Menderes, in modern Turkey).
Family In the Theogony, Hesiod made the three thousand river-gods the sons of the Titans Oceanus and Tethys, though Cayster is not mentioned by name among them.Hesiod, Theogony 337–45 Cayster was the father of Ephesus, who gave his name to the nearby city of Ephesus, and later along with Coresus founded the sanctuary of Ephesian Artemis.Pausanias 7.2.7
Mythology According to a late version, the Cayster actually took its name from a mortal named Cayster, son of the Amazon Penthesilea, who married Derceto in Ascalon and had Semiramis by her.Etymologicum Magnum s.v. 447.40
While describing the disastrous ride and fall of Phaethon from the sun-chariot, Philostratus the Elder noted that the swans scattering around would sing the tale to Cayster and Ister.Philostratus the Elder 1.11
Worship According to Strabo, Cayster had a hero-temple shared with the hero Asios very close to the homonymous river.Strabo 14.1.45
References
Bibliography Hesiod, Theogony, in The Homeric Hymns and Homerica with an English Translation by Hugh G. Evelyn-White, Cambridge, MA., Harvard University Press; London, William Heinemann Ltd. 1914. Online version at the Perseus Digital Library. Pausanias, Description of Greece with an English Translation by W.H.S. Jones, Litt.D., and H.A. Ormerod, M.A., in 4 Volumes. Cambridge, MA, Harvard University Press; London, William Heinemann Ltd. 1918. Online version at the Perseus Digital Library. Philostratus the Elder, Imagines, translated by A. Fairbanks, Loeb Classical Library No, 256. Harvard University Press, Cambridge, Massachusetts. 1931. . Internet Archive Strabo, The Geography of Strabo, edition by H.L. Jones. Cambridge, Mass.: Harvard University Press; London: William Heinemann, Ltd. 1924. Online version at the Perseus Digital Library.