The transnational and transmedial dimensions of media and communication throughout history have not always been adequately recognised. In this research report we propose the concept of entanglement as a means of better understanding the dynamic interconnectedness of media across semiotic, technological, institutional and political boundaries in history. Entanglement is a concept that can be employed in order to problematize the presumed points of departure and the linear understandings of development, production and reception that often characterize media-history scholarship. Moreover, an entangled media histories perspective throws light on social and communicative action in general and can thus enrich any historical study. The report outlines, and invites discussion of, the theoretical and methodological framework of the transnational network ‘Entangled Media Histories’, which since 2013 has been a forum for co-operation in research and teaching between media historians in Sweden, Germany and Great Britain.