Present-day international humanitarian law has grown from two main sources: the Law of Geneva, i.e. a body of rules which protect victims of war, and the Law of The Hague, i.e. those provisions which affect the conduct of hostilities. The author examines the different policies which are behind these two branches of international humanitarian law and traces their history up to the 1974-1977 Diplomatic Conference which, by adopting Additional Protocol I, brought about their convergence. While the ICRC undoubtedly gave rise to the Law of Geneva, its contribution to the development and implementation of the Hague Law has been less explicit. The author argues that any involvement in humanitarian law today implies a concern for both domains, which now are inseparable parts of modern international humanitarian law.