What is the content of Europeanization? Which causal relationships should be explained? Which theory should be used? In answering these questions, the article forwards a conceptualization of Europeanization based on Historical Sociology and Social Constructivism, which implies a departure from the practice in the current Europeanization literature to concentrate on the contemporary with a narrow focus (EU-ization) at the expense of the historical with a broad focus (Europeanization). It is suggested that the causal relationships to be explained are the transfer of European ideas across time and space using a ?present-as-reality? definition of the European idea set. In doing so, it becomes apparent that Europeanization cannot be accepted as either static or something that is solely connected to the EU, and that Europeanization has been characterized by diffusion patterns going both into and out of Europe and sociological processes involving subtle shifts in process, structure, agents and conceptions of ?Other? and ?Significant We?.