Interdisciplinary capacities of intellectual history make it possible, through studying the text in the context, to understand well what positions in relation to the war, the government, their people, and military opponents were occupied by the rulers of public opinion - writers, scientists, artists and cultural figures under the influence of the “August experience” characteristic of the initial period of the Great War. However, turning to collective initiatives - manifestos, open letters, statements that were supported and signed by dozens and hundreds of people is associated with solving a complex set of issues. They are those of authorship, motivation, the influence of individual political and ethical principles on group decisions, the definition of leaders and marginals, the comparison of rational attitudes to achieve a propaganda effect and unconscious emotions, etc. The article attempts to provide answers to the questions based on studying the appearance circumstances and significance of the so-called “Manifesto of the Ninety-Three to the Cultural World” - an open letter signed by prominent German intellectuals refuting the propaganda claims of the Entente about German atrocities and the destruction of cultural values in Belgium. The authors tried to refute the accusations and emphasize the purely defensive nature of the actions of the German soldiers. However, the propaganda effect of the letter turned out to be the opposite of what was expected. For the public opinion of the Entente countries, it became a symbol of the ideological and propagandistic justification of German aggression and served as the basis for the exclusion of German intellectuals from the world academic community.