When the Roman poet Juvenal asked 'Quis custodiet ipsos custodes? ' ('Who watches the watchmen? ') he was questioning the integrity of guards posted to ensure his wife's fidelity. More recently the phrase has been generalized to challenge authority, the utility of regulators, and schemes of quality assurance.

Pronunciation

1. 1(Classical) IPA: /kʷis kusˈtoː.di.et ˈip.soːs kusˈtoː.deːs/, [kʷɪs̠ kʊs̠ˈt̪oːd̪iɛt̪ ˈɪps̠oːs̠ kʊs̠ˈt̪oːd̪eːs̠]
   

2. 2(Ecclesiastical) IPA: /kwis kusˈto.di.et ˈip.sos kusˈto.des/, [kwis kusˈt̪ɔːd̪iet̪ ˈipsos kusˈt̪ɔːd̪es]