With the end of the Cold War, we observe two major changes in the way the Organisation of African Unity (OAU) and the African Union (AU) sought to legitimate themselves. First, the focus shifted from merely facilitating cooperation to demonstrating that the work of the OAU and later the AU actually made a difference ‘on the ground’; that it led to peace and development, to integration, and to a stronger representation of African interests in global institutions. Second, the AU sought to build its legitimacy on the notion of working not only for and with African states, but also for and with the African people. Legitimation thus increasingly focused on the principles of ‘democracy’, ‘human security’, or ‘human development’. As the chapter reveals, various dynamics in the organizational environment facilitated these changes, but norm entrepreneurship by the OAU/AU bureaucracy was central.