This paper, drawing on a newly published book edited by James Renton and Ben Gidley, explores the changing ways the figures of the Jew and the Muslim have been used to mark the borders of European identity – an identity that remains normatively Christian despite a rhetorical drift to secularism, the “Judeo-Christian” or the multifaith. The paper argues that these two figures have been constitutive outsiders shaping what Europe is. Both forms of racialisation have mutated over time and in different parts of the continent, and understanding this, the paper argues, requires a rigorously comparative and rigorously diachronic perspective. Each form of racialisation has occurred independently of the other, but more often they have taken on meaning in relation to each other, and so analysing both anti-Jewish and anti-Muslim racism is enhanced through case studies which excavate their relationship.