In this episode, Morgane Labbé, Professor at the École des Hautes Études en Sciences Sociales in Paris, discusses the role of statistics and maps within Eastern and Central European nation-building. She emphasizes the need to consider the historical rise of statistics as a form of mathematical science used to legitimise the nation and its boundaries. Morgane also highlights how this tradition gave rise to the symbolic significance of the national census among the new states that emerged across this region during the nineteenth and early twentieth centuries. Beginning in the 1920s, censuses not only became a tool used to legitimise the new nation-state via numerical dominance but mechanisms of mass mobilisation and mass participation in the process of nation-building. In practice, however, these censuses more often recorded a broader diversity of belonging. This, in turn, gave rise to a form of administrative categorisation that would always take place afterwards and focus on recoding or ignoring these responses, reflecting the real “fabric” of what actually constituted national majorities and minorities. "Eastern Europe's Minorities in a Century of Change", a podcast series on the history of minorities and minority experiences in twentieth-century Central and Eastern Europe prepared by the BASEES Study Group for Minority History to mark the Institute for Historical Research’s centenary. The co-conveners of the Study Group are Olena Palko (Birkbeck) and Samuel Foster (University of East Anglia)