The contrast between the European civil wars in the first half of the century and the contribution of a uniting and united Europe to the maintenance of the ‘free’ Western world in the second half is so marked as to suggest that no single explanation of this massive change will suffice. Only an analysis of conjunctures can reveal what divides and unites the countries of Europe and assess Europe's impact on the world. This paper combines an assessment of four lengthy periods (pre-First World War, interwar, divided Europe and post-Cold War) with a secular view of Europe's position and role in world politics and the international economy. It consists of two parts: a brief account of the basic thesis and of the characteristics of the idea of ‘Europe’, and an historical analysis of the four periods.