The article is devoted to the problem of the genesis of the mythologeme about the conspiracy of secret societies among the Russian authorities and the political establishment. Based on the thesis formulated in another work about the predominant importance of the reports of Russian diplomats about the events in Spain in comparison with the statements of K. Metternich regarding the Italian revolutions for folding the mythologeme of the 1820 model, the author uses this research paradigm in order to trace the evolution of the concept in 1821-1825. Numerous denunciations of Polish students and officers are analyzed, which determined the transformation of the mythologeme: by 1825, the role of the protagonist in it was taken not by the mythical Paris Committee, but by Polish patriots. This is what explains the peculiarity of the very rst reaction of K. V. Nesselrode on the events of December 14: according to his initial statement, a riot of Polish officers took place in the capital, the purpose of which was to plunge the empire into anarchy and confusion. As appendices, reports of the Spanish diplomat Paez de la Cadena, who witnessed the Decembrist uprising and recorded in detail the rhetoric of the head of the Russian Foreign Ministry, are published.