Alsace-Lorraine Empress Eugénie William I France
France was able to make the claim that the provinces of Alsace-Lorraine were indeed part of France and not part of Germany by disclosing a letter sent from the Prussian King to the Empress Eugénie that Eugénie provided, in which William I wrote that the territories of Alsace-Lorraine were requested by Germany for the sole purpose of national defense and not to expand the German territory.