In grade school I heard about how Yellow Journalism helped the Spanish-American War to erupt. I consider that the first instance of fake news.
From Wikipedia: https://en.wikipedia.org/wiki/Propaganda_of_the_Spanish%E2%80%93American_War
Men such as William Hearst, the owner of The New York Journal was involved in a circulation war with Joseph Pulitzer of the New York World and saw the conflict as a way to sell papers. Many newspapers ran articles of a sensationalist nature and sent correspondents to Cuba to cover the war. Correspondents had to evade Spanish Authorities; usually they were unable to get reliable news and relied heavily on informants for their stories. Many stories were derived from second or third hand accounts and were either elaborated, misrepresented or completely fabricated by journalists to enhance their dramatic effect.
The Spanish-American War began after Spain was blamed for the sinking of the USS Maine. But the war was provoked by powerful U.S. newspapers and served the interests of big banks. By James Perloff
Spanish-American War: Trial Run for Interventionism
http://www.thenewamerican.com/culture/history/item/12338-trial-run-for-interventionism
Hearst learned everything he knew from Stead. That includes his manipulations that led to the Spanish American War.