This interdisciplinary thesis is the first dedicated study of German Jewish patronage of French Impressionist and post-Impressionist art in Wilhelmine Germany. It investigates the disproportionately strong impact of German Jewish patronage from three perspectives. It examines the significance of Paul Cassirer's modernist art dealership, the prominence of German Jewish art collectors and their modernist art collections and the presence of German Jewish sponsorship at the Nationalgalerie Berlin, the Pinakothek Munich and the Stadelsche Kunstinstitut in Frankfurt am Main. First it examines Impressionism as the 'painting of modern life' in its original French context, focussing on French Jewish dealer-patrons and collectors whose association with French modernist artists influenced not only its iconography, but also involved French Jews in modern art promotion and marketing. The French model serves as a basis for understanding the reception of such art amongst a liberal circle of Germans and German Jews. The study examines the Wilhelmine reaction to French modernism and shows how antagonism toward Jews and France was often linked and interpreted by conservatives as 'alien elements' in nationalist Germany, thus highlighting Impressionism as a threat of a new Weltanschauung. This thesis suggests that although some German Jews acculturated to the dominant Wilhelmine culture, the championing of modernist art actually emphasized their Jewishness and their role as the 'Other' in German society, despite their patriotism. Yet, in the long run, German Jewish taste for the avant-garde had as much influence on German modernism as German taste had on Jews. The study hypothesizes that German Jews embraced French Impressionism as an 'iconography of inclusion' that coincided with their own experience of modern life and thus their patronage served as a component in the construction of their secular identities. The study concludes that strong German Jewish patronage changed the modern art market irrevocably and by doing so it was not only a turning point for the writing of modern art histories, but also for the reassessment of German Jewish cultural identities, thereby proving that the history of modernist European art patronage encompassed also a history of ideas