Quis custodiet ipsos custodes? - "Who watches the watchmen?"
Quis custodiet ipsos custodes? ("Who watches the watchmen?") is a Latin phrase found in the work of the Roman poet Juvenal from his Satires (Satire VI, lines 347–348). The original context deals with the problem of ensuring marital fidelity, though the phrase is now commonly used more generally to refer to the problem of controlling the actions of persons in positions of power, an issue discussed by Plato in the Republic. It is not clear whether the phrase was written by Juvenal, or whether the passage in which it appears was interpolated into his works.