Chapter 5 deals with the creation of the Islamic State and of the movement ISIS. Their literalist and expressly politicised interpretations of doctrine have led it to espouse exclusionary and aggressive notions of the umma. The community of the faith becomes identifiable with a revived Caliphate, based on territorial dimensions and purist standards of community membership. The chapter elaborates on the trajectory of radical Islamism and points to areas of difference with al-Qa‘ida. It also argues that the brutality of ISIS against the Shi‘a and others subverts its avowed expansionist aim, as many within the Muslim world as well as non-Muslim powers have sought to destroy it. But, as the chapter demonstrates, military defeat and territorial retrenchment are unlikely to exorcise the allure, in receptive quarters, of a purportedly ‘authentic’ but highly romanticised umma.