This chapter addresses the evolution of the responsibility to protect concept from September 1999 to its adoption in the World Summit Outcome Document of September 2005. It covers Kofi Annan’s ‘dilemma of intervention’, some early human security initiatives by Canada including the International Commission on Intervention and State Sovereignty (ICISS) and its report The Responsibility to Protect which first articulated the moniker as well as the concept, the High-Level Panel on Threats, Challenges and Change and the Secretary-General’s report In Larger Freedom, the negotiations and Outcome Document of the World Summit, and the early incorporation of protection of civilians within Security Council resolutions. Throughout this narrative, the importance of sustained advocacy by key individuals—including Kofi Annan, Lloyd Axworthy, and Gareth Evans among others—is presented as vital to the evolution (in theory and in practice) of the responsibility to protect.