Since the time of the historico-political polemics between František Palacký and Constantin von Höfler in the middle of nineteenth century, the term “national” has been used by Czech historians to identify the character of the Hussite wars. The execution of Jan Hus in Constance as well as the proclamations of the crusades against the Hussites in Bohemia are defined as “an insult to national honor” (František Palacký), and they produced the Taborite movement as “a national peasant war of the Czech under the flag of religion against the German nobility and the supremacy of the German Emperor” (Friedrich Engels / Josef Macek), while the military invasion released a “national” which spread among the whole society (František Šmahel). To what extent does the term “nationalism of defense” and its derivates befit the study of the contradictions that existed between the Czechs and the Germans in the Bohemian kingdom of that period? This paper proves that the Prague Hussites did not consider the Bohemian Germans their “natural foes” but did so of the crusaders who came from the German lands along with King Sigismund. The author argues that the Prague Hussites had not a cultural, but a political xenophobia focused on the foreign German invaders.