This article concludes a study tracing the role of élite theory in Michels' development from revolutionary socialist to Fascist ideologue. It argues, first that the laws of oligarchy and élite circulation as expounded by Mosca and Pareto made the Fascist seizure of power appear historically necessary. It then examines the contribution which the experience of Fascist rule made to the further development of élite theory in Michels' work; his use of the theory to give scientific status to the self-image of the Fascist élite and the charismatic claims of its leader; his legitimation of authoritarian government and nationalist policies through the theories of mass psychology. The conclusion argues that what distinguished Michels from other Fascist ideologues was his use of scientific categories, and locates the origin of these categories in the historical experience of pre-world war Europe.