In the 1930s in the USSR, the paradigm of the main historical narrative is changing. The new culture of history also affects the conceptualisation of the history of culture. This is reflected not only in the texts of academic papers and books, but also in museum exhibitions. This publication deals with the materials (from the funds of the Central State Archive of Historical and Political Documents of St. Petersburg) on the history of musealisation of St. Isaac’s Cathedral in Leningrad in the late 1930s. These historical sources demonstrate the heterogeneity and inconsistency of the authoritative discourse, in which there was no clear answer to the question: how to combine the current agenda and the texture of the monument.