Since the beginning of the Nuremberg trial, the status of the individual in international law has changed. This change is intimately connected with the rights of defence in criminal proceedings, especially in the context of international criminal proceedings. Today, as a matter of right, the individual may make certain claims in international law, and especially in international criminal law and international human rights law related to criminal procedure and substantive criminal law, without relying on a State to make them on his or her behalf. This brief article explores this development of the international legal personality of individuals. It surveys the sources and evidence of international law that can be used by individual defendants in international criminal cases. Finally, it considers an important limit of this development, concerning whether acts of individuals and other private actors “in the field” affect the development of customary international criminal law.