Cypselus (Greek: Κύψελος, Kypselos) was the first tyrant of Corinth in the 7th century BCE.
With increased wealth and more complicated trade relations and social structures, Greek city-states tended to overthrow their traditional hereditary priest-kings; Corinth, the richest archaic polis, led the way. Like the signori of late medieval and Renaissance Italy, the tyrants usually seized power at the head of some popular support. Often the tyrants upheld existing laws and customs and were highly conservative as to cult practices, thus maintaining stability with little risk to their own personal security. As in Renaissance Italy, a cult of personality naturally substituted for the divine right of the former legitimate royal house.
After the last traditional king of Corinth, Telestes, was assassinated by Arieus and Perantas, there were no more kings; instead prytanes taken from the former royal house of the Bacchiadae ruled for a single year each. Cypselus, the son of Eëtion and a disfigured woman named Labda, who was a member of the Bacchiad family, the ruling dynasty, usurped power, became tyrant and expelled the Bacchiadae.
According to Herodotus the Bacchiadae heard two prophecies from the Delphic oracle that the son of Eëtion would overthrow their dynasty, and they planned to kill the baby once it was born; however, Herodotus says that the newborn smiled at each of the men sent to kill it, and none of them could go through with the plan. An etiological myth-element, to account for the name Cypselus (cf. κυψἐλη, kypsele, "chest") accounted how Labda then hid the baby in a chest, and when the men had composed themselves and returned to kill it, they could not find it. (Compare the infancy of Perseus.) The cedar chest of Cypselus, richly worked with mythological narratives and adorned with ivory and gold, was a votive offering at Olympia, where Pausanias gave it a minute description in his 2nd century AD travel guide.