In the work of the International Law Commission (ILC) on ‘the general principles of law’ in Article 38(1)(c) of the Statute of the International Court of Justice, one question has given rise to an inordinate amount of controversy: does this category of principles include principles formed within the international legal system or does it embrace only principles derived from national legal systems? In the draft conclusions adopted on first reading in 2023, the ILC accepts the existence of general principles of law formed within the international legal system, but only in a very narrow manner. Prominent commentators have argued that such a narrow approach is correct. It has been contended, furthermore, that the category of general principles of law formed within the international legal system is an innovation of the ILC's, and one that lacks any real support in State practice. These views are based on assumptions to the effect that the traditional view concerning the meaning of Article 38(1)(c) was that it referred only to general principles of law derived from national legal systems. The present article takes issue with these assumptions. It seeks to prove, by an analysis of the position in 1920 when the Statute was drafted, of the practice of States, both before and after 1920, and the writings of leading commentators, that general principles of law formed within the international legal system are no less part of ‘general principles of law’ than general principles of law derived from national legal systems.