David Nirenberg, an internationally renowned specialist in the relationships between Jewish, Christian, and Islamic cultures throughout history, focuses in this essay on the concept of the "Jewish" as a consistent political idea in Western history. The emphasis is not on Judaism as a historical and lived religion, but rather on the attribute "Jewish" as a figure in Christian thought. Without understanding these intellectual traditions, one cannot grasp either Carl Schmitt's political theology or the images of Judaism that Schmitt's theory produced. On his intellectual journey, Nirenberg illustrates through early Christian, medieval, and modern examples how "Judaism" and "Jewish" have gained significance as terms in political language. Thus, "Jewish" was a central concept in Christian political theory.