The First World War and the break-up of Europe's continental empires marked not only a triumph of democratic principles, but also one of nationalism.¹ While the erstwhile empires had relied on dynastic, historic and religious loyalties that allowed them a flexible policy towards their many ethnic groups,² the new countries emerging after 1918 legitimized themselves by equating 'state" with "nation", and defined their population as homogeneous, regardless of its actual degree of heterogeneity. Due to the complexity and multi-ethnic structure of the distribution of the population, particularly in Central and Eastern Europe, the Allies' redrawing of the political map at the Paris Peace Conferences of 1919–20 did not realize Woodrow Wilson's vision of the 'self-determination of peoples".³ Rather, the cessation of large territories and their inhabitants to ethnically different nation-states suddenly created a group of approximately 35 million people who were defined as "minorities' in their new or remodelled countries. While nine million of these lived in Western Europe (mostly in Germany, Italy and Spain), about 26 million were spread across Eastern Europe — primarily in Poland, Czechoslovakia, Yugoslavia and Romania.⁴ The Allies tried to safeguard them by imposing upon the new host states treaties which placed ethnic minorities under international rule and were guaranteed by the newly founded League of Nations.⁵