This chapter focuses on some of the ways in which states and their citizens have sought to describe and identify terrorists and terrorism, and why they have adopted certain historical tropes and language in the process. Modern states have utilised a number of long-standing historical tropes as lenses through which to view the nature and threat of modern sub-state terrorism, in turn adopting corresponding historical narratives to condemn and counter terrorism. ‘History’ has therefore proved a useful tool in helping states legitimate counterterrorism policies. ‘History’ has also played a role in the scholarship of Terrorism Studies, with commentators looking to the past in order to differentiate between ‘old’ and ‘new’ terrorism. The historical evidence for the old/new terrorism thesis may be fragile, but the presentation of ‘new terrorism’ – characterised by religious fanaticism (notably Islamic extremism), irrationality and unlimited violence – has drawn heavily upon the historical trope of civilisation struggling against barbarism. Terrorists have become the paradigmatic new barbarians of our current political era. The wider cultural resonances of this linguistic association between barbarism and terrorism is important because, as Crenshaw rightly argues, language is not neutral. By using the language of barbarism in reference to terrorism, states are able to situate terrorists immediately within a deep cultural understanding of threat and the Other.