The document shown here is a telegram, dated September 17 1927, sent by the American philanthropist John D Rockefeller JR to Sir Eric Drummond, on the occasion of Rockefeller having donated 2 million dollars in order to build a new library for the League.
Rockefeller was a fervent pacifist and felt that the best way to prevent another war from happening was to make knowledge accessible to everyone. He wanted the League Library to become an international centre of knowledge through his donation.
The telegram is in the archives of the League, which were transferred to the United Nations in 1946 and are housed at the UN Office in Geneva. The archives were inscribed on the UNESCO Memory of the World register in 2010.