The United States National Anthem was written by Francis Scott Key after he witnessed the horrendous battle with the British Navy at Fort McHenry during the War of 1812. As bombs exploded and rockets flew overhead, Key's continued to watch the battle until dawn broke. Key expected to find the city of Baltimore under British control, by he was stunned to see instead a shredded remnant of the American flag still flying in the early morning sun. This sight inspired Francis Scott Key to write a poem that was to become our National Anthem, "The Star-Spangled Banner." The song became America's national anthem in 1931 after it was set to a tune composed by John Stafford Smith.