In this article we take a discourse–historical approach to illustrate the significance of George W. Bush’s (2001) declaration of a ‘war on terror’. We present four exemplary ‘call to arms’ speeches by Pope Urban II (1095), Queen Elizabeth I (1588), Adolf Hitler (1938) and George W. Bush (2001) to exemplify the structure, function, and historical significance of such texts in western societies over the last millennium. We identify four generic features that have endured in such texts throughout this period: (i) an appeal to a legitimate power source that is external to the orator, and which is presented as inherently good; (ii) an appeal to the historical importance of the culture in which the discourse is situated; (iii) the construction of a thoroughly evil Other; and (iv) an appeal for unification behind the legitimating external power source. We argue further that such texts typically appear in historical contexts characterized by deep crises in political legitimacy.