The prominent historian Karl Bosl, who during World War II had been a high school teacher in Ansbach, Franconia, intimated that he had been critical of the Nazis and asserted that he had belonged to a small group that engaged in active resistance; one of its members, Robert Limpert, was apprehended by the Nazis and brutally put to death just hours before the Americans arrived. The present study, based on a large number of unpublished official and private documents, records Bosl s manifold links to the Nazi regime and reveals that as late as December 1944 he delivered a stirring lecture before Ansbach s Nazi leadership in which he extolled the struggle for the preservation of Hitler s Greater German Reich; yet as early as September 1945 he vigorously condemned Nazism at a ceremony at Limpert s grave. The documents attest also to how Bosl succeeded in persuading Ansbach s Denazification Tribunal that he had risked his life opposing the Nazis. An unpublished account allows for a detailed reconstruction of the daring, little-known activities of young Limpert and his three classmates.