This research focuses on the absorbing society, and examines a process by which immigrants entered and changed the cultural core of the absorbing society. It analyzes the development of an ethnic holiday, the traditional ethnic Mimouna holiday of North African immigrants in Israel, into a national holiday and into part of the dominant culture. The research concludes that this process evolved mainly as a result of the political activism of immigrants from North Africa and a weakening of the hegemony. It may also illuminate the sometimes crucial role of immigrants in moving the boundaries between the center and the periphery.