People - Ancient Greece: Eurybatus He was an Ephesian who betrayed Croesus to Cyrus.
Eurybătus in Harpers Dictionary of Classical Antiquities
（Εὐρύβατος). An Ephesian, whom Croesus sent with a large sum of money to the Peloponnesus to hire mercenaries for him in his war with Cyrus. He, however, deserted to Cyrus, and betrayed the whole matter to him. In consequence of this treachery his name passed into a proverb among the Greeks (in Ctes. 43).
Eurybatus in Wikipedia
Eurybatus can mean:
In Greek mythology/history
* Eurybatus, one of the Argonauts 
* One of the commanders of the Battle of Sybota
* A warrior who slew the beast lamia
* One of a pair of chthonic tricksters who disturbed Heracles while he served Omphale (Graves, Robert, The Greek Myths 1955.)
* Eurybatus of Ephesus, who betrayed Croesus to Cyrus 
* Eurybatus, a leader during the Peloponnesian War