Abstract
This study aims to broaden and refine our knowledge on radicalisation by applying a different lens derived from communication sciences, it also aims to minimise the bias resulting from the several studies focusing on one movement—the Islamic State. The research utilises a qualitative thematic analysis triangulated with a quantitative content analysis to compare 30 documents: 15 belonged to an old radical movement—the Red Brigades and 15 to a new radical movement—the Islamic State, to explore possible strategic communication patterns used by both organizations to establish their legitimacy among their target audiences. The findings revealed a similar division in the construction of the documents of both movements under four main themes, high and equivalent proportions in the representations of ‘violence’, and an extensive concentration of ideological terms in the Islamic State documents compared to a large focus on organizational aspects in the Red Brigades documents. The principal and wide gap existing between both movements is related to the organisational tactics. Likely to be one of the main distinctions contributed by modernisation in the world today.