The development of the field can be divided into four stages: (I) the late eighteenth and nineteenth centuries, when nationalism first emerged, and most interest in it was philosophical; (II) the period from the First World War until the end of the Second, when nationalism became a subject of formal academic inquiry; (III) the post-war period from 1945 to the late 1980s, when several sociologists and political scientists developed general theories of nationalism in the context of worldwide decolonization and the 'ethnic revival' in the West; and (IV) the period following the fall of communism in 1989, which led to a surge of interest in nationalism and the crystallization of nationalism studies as a field.[1]