The tasks of the Mendelssohn-Gesellschaft as set out in its statutes include "the collection of documents, letters, manuscripts, works of art, mementoes, books and other objects, for the purpose of publishing them independently or with the assistance of third parties, or of making them accessible to the public as originals or as copies, for example via the Mendelssohn Archives kept by the Staatsbibliothek Berlin Preussischer Kulturbesitz (State Library of the Berlin Prussian Cultural Heritage Foundation)" (Section 2).
Usually, this source material is acquired from booksellers or art dealers, and often at auctions. In other instances, these records are gifted to our association by members of the Mendelssohn family or by sponsors. In particular autographs, original illustrations and rare editions are handed over to the Staatsbibliothek, where they are kept in the Mendelssohn Archives and made accessible to researchers. In this way, the Mendelssohn-Gesellschaft was the first association sponsoring the Staatsbibliothek following World War II. The acquisitions were presented to the public in three exhibitions held in 1976, 1987 and 1992/93.
In 2003, Ingeborg Stolzenberg, former chairwoman of the Mendelssohn-Gesellschaft published the most comprehensive index thus far of the Mendelssohn archival materials in "Das Mendelssohn-Archiv der Staatsbibliothek zu Berlin. Bestandsübersicht" (Inventory of Archival Materials of the Mendelssohn Archives kept by the Staatsbibliothek zu Berlin) by Hans-Günter Klein. The depository comprises hundreds of individual artifacts, among them note manuscripts and letters by Felix Mendelssohn Bartholdy and a part of the estate of the instrument maker Nathan Mendelssohn.