Nemo iudex in causa sua
Nemo judex in causa sua (IPA: [ˈne.mo ˈju.dɛks in ˈkau̯.sa ˈsua]; also written as nemo [est] judex in sua causa, in propria causa, in re sua or in parte sua) is a Latin brocard that translates as "no one is judge in his own case". Originating from Roman law, it was crystallized into a phrase by Edward Coke in the 17th century and is now widely regarded as a fundamental tenet of natural justice and constitutionalism.