To develop a more fine-grained picture of how the theory of general relativity was received and elaborated from 1914 until 1924, we move outside the personal networks of its creator, Albert Einstein. We set aside the question when and why Einstein himself came to recognize that the new field physics required higher mathematics and focus on the cross-fertilization between mathematics and physics that contributed to the theory. The breakdown of disciplinary boundaries had a greater impact on academic politics in Germany, as the intrusion of mathematics heightened tensions that had long been brewing within the German physics community. A second factor contributing to the tensions was the increasing prominence in the community of German physicists of those of Jewish extraction. We examine these phenomena in two localities, Göttingen and Berlin that serve as focal points for polarization in the natural sciences. First, we discuss the openness in their scientific approach and in their recruitment policy of the paladins of Göttingen—Felix Klein and David Hilbert—and then proceed to trace the fruits of that policy in the successor generation that was largely composed of Jews. We then look at Einstein in Berlin, and more specifically, at how his “conversion” to Zionism in 1920 crystallized his idiosyncratic views on cultural politics that alienated him from others in the Berlin community, including some of his Jewish colleagues. We examine four incidents that undergird his solidarity with Hilbert, a “Gesinnungsgenosse,” who believed that belonging to the international community of scientists took precedence over any sense of patriotic duty or ethnic identity.