Conflicts of all kinds are inevitably accompanied by polemical and hostile communication. Under favourable circumstances and where necessary resources were found, such communication could grow to a veritable media campaign even in pre-modern times. The September School on “Communicating Discord: The Media of Polemic in the Late Middle Ages and Early Reformation” suggests to analyse how disapproval and abuse were communicated not only in various social contexts, but also through various channels and media (written, oral, pictorial). The focus will be on the Holy Roman Empire from the fourteenth to early sixteenth centuries, and thus on a space and time that witnessed a number of social upheavals, military conflicts and religious novelties, including the emergence of Hussite and Lutheran Reformation. In this way, the Summer School attempts to overcome the traditional separate treatments of national histories and historical eras. The relevance of the epochal divide between the Middle Ages and the Reformation should be tested against the development of communication media, with due attention given to both the revolutionary potential of technological progress and the long-term stability of cultural and communicative practice.