ABSTRACT. Is homogenising nationalism a consequence of industrialisation? This view has been most forcefully and systematically advanced by Ernest Gellner. The article contests this approach by focusing instead on militarism and militarisation. It therefore identifies the key role of the mass army as presaging the era of mass nationalism and cultural homogenisation. Drawing on a range of authors from history, sociology and political science, the relationship is found to be reciprocal and symbiotic. A preliminary exploration on the possibility of early modern (or pre-modern) forms of cultural homogenisation is preceded by a critical assessment of Gellner's interchangeable use of the terms culture, language and ethnicity.