The monograph for the first time reveals the ideological origins and historical and philosophical meaning of the appeal to Catholicism of a part of Russian society of the 19th century. The author establishes the relationship between the views of Alexander I and M.S. Lunin, interprets the work of the great thinkers P. Ya. Chaadaev and Vl. S. Solovyov in a new way. The source basis is the Archive of the Slavic Library of Paris, founded as a collection of materials from the Russian emigration by the Jesuit Prince. I. S. Gagarin. The book is intended for historians, cultural scientists, philosophers and everyone interested in the intellectual history of the past.