One Hellanodikas was a type of Greek public official termed generally the agonothetes (English transliteration), Ancient Greek: Ἀγωνοθέται, Agōnothetai, meaning game organisers), magistrates chosen specifically for the purpose of establishing and maintaining public games.
Originally, perhaps, if only in legend, there may have been only one Hellanodikas, but this expanded, reaching as high as twelve members and then settling on ten in 348 BC.
In the ten months preceding the games, the Hellanodikai lived in a specially made building in Elis, called the Hellanodikaion.
While staying at the Hellanodikaion, they were trained by the nomophylakes (νομοφύλακες, meaning 'guardians of the law') in the rules and regulations of the olympic games.
While bribery and cheating among the athletes was commonplace, there was only one recorded case of corruption among the judges, where a Hellanodikas won two equestrian events.