The archival material pertaining tothe real estate interests of the family is plentiful, going back to nearly
the entire 19th and 20th centuries. Of particular interest is the correspondence between the Granduke Nicholas
Mikailovic Romanov and Princess Leonilla Bariatinsky, mother of Antonietta Chigi, during the Russian revolution.
The library collection is divided into two sections: the 17th century section, the so-called "Library of the
campaign of Prince Augustin Chigi", composed mostly of theatrical booklets of the 17th century, the other 19th-20th
century section, that documents the various cultural and scientific interests of the family. Very important
librarians have added to the collection, like Redig De Campos, once director of the Vatican Museums, or the
librarian Beatrice Canestro Chiovenda, art historian.