There is virtually no treatment of republican political cleavages or political culture in the literature on European political development. This article fills part of this gap by examining the consequences of republican political culture for the history of nations and nationalism. I argue that the republican question was a central political cleavage in Europe in the nineteenth and early twentieth centuries, but that it has been largely overlooked, or reduced to the politics of class or to the politics of nation. The article critically assesses some of the central elements of standard political histories of nationalism, in light of the importance of republican politics. This exercise includes a sketch of the republican challenge to dynastic states, and a more detailed discussion of two individuals who figure prominently in every history of nationalism: Renan and Mazzini. It also includes a discussion of the relationship of nationalism and marxism, in light of the analysis of republican patriotism in the first part of the article.