The relationship between Christianity and other religions is a vital issue in the world today. This book provides a fresh perspective by exploring how Christian theology has been shaped over two millennia by interaction with its original religious “other”, continuing Judaism.It begins by describing the origins of the “classic framework” in Christianity that correlates claims about the gospel with judgments about Judaism as resistance to the new thing God has done in Jesus Christ. This framework binds Christianity to the task of interpreting Jewish presence, which then renders engaging with Judaism as well as rehearsing judgments about it integral to Christian theology’s development. The central chapters of the book demonstrate this in relation to three pivotal periods of Western history: 1050-1300 CE, early modernity and the first half of the twentieth century. They reveal the classic framework to have been remarkably resilient, despite sometimes radical adaptation, before, in and after modernity.The insights of Franz Rosenzweig about Judaism as Christianity’s “internal foe” resonate deeply with the book’s historical analysis. Does this mean that non-relativistic Christian theology must remain intrinsically anti-Jewish? The book concludes that it need not, if it can renounce its historic stance of hermeneutical comprehension.