In times of great political unrest and disorientation, societies generally invent and reinvent myths. As unrest and disorientation were among the most striking characteristics of the Weimar era, it is not surprising that the bicentenary celebrations of Moses Mendelssohn’s birth, held in 1929, constituted the peak of the Enlightenment philosopher’s popularity as a German-Jewish patron saint. This article argues that the commemoration of Mendelssohn on the eve of catastrophe, four years before the Weimar Republic’s collapse, serves as a particularly precise indicator of ambivalent German-Jewish agency at the time, due to its political, social, and cultural implications. Whereas the bicentenary celebrations—featuring the Republic’s most prominent representatives, state-of-the-art exhibitions, cultural events in prestigious locations, and extensive media coverage—attest to the considerable leeway German Jewry had in shaping social reality, the continuing absence of Mendelssohn in the canon of German poets and thinkers illustrates the limits of German-Jewish agency in the cultural imaginary of the German nation.