After World War II Dr. Kurt R. Eissler (1909–1999) and a small group of psychoanalysts who knew Sigmund Freud personally, including Heinz Hartmann, Ernst Kris, Bertram Lewin and Hermann Nunberg, decided to preserve Freud's letters and papers in a single archive. The Library of Congress, Dr. Eissler wrote, agreed in a legal "instrument" to accept as a donation all documents collected by the Archives, and to make them accessible to scholars. By the 1980s Dr. Eissler, with the help of Anna Freud, had collected thousands of tapes, letters and papers for that archive.