The article analyzes the correspondence of E. G. Polonskaya and K. A. Fedin, members of the literary group Serapion Brothers, formed in Petrograd in 1921. The short but bright period of the existence of the association is still of interest to many researchers. Particularly relevant is the study of documentary sources, which make it possible to fi ll in the factual gaps in the history of both the Serapion fraternity itself and the relationships of its individual members. The author of the article draws on previously unpublished materials from the archive of K. A.