What has been interpreted as terror can be interpreted as security. The standard histories about organisations such as the Irish Republican Army, based on claims about terror on the one hand or revolution on the other can be re-read on the basis of (also standard) narratives about security, with security implying much greater legitimacy than terror.This thesis makes usage of Jef Huysmans thought to analyse the IRA as a security agency and the socio-political processes where it is embedded, in order to show how the shift from terror narratives to security narratives recasts the relationship between legitimacy and violence, both in relation to the IRA and to the state. It is not only a matter of whose history gets told, but how specific forms of narratives work to shape claims about what counts as legitimate violence. Therefore, organisations like the IRA can be better understood when interpreted as organisations that have legitimacy over a population instead of starting from the assumption of their illegitimacy.