“The Star-Spangled Banner” became the United States national anthem in 1931.
The song began as a poem written by Francis Scott Key after he witnessed the American defense of Fort McHenry during the Battle of Baltimore in September 1814. Its original title was “Defence of Fort M'Henry,” and the words were later set to the melody of a popular British song.
The song was widely performed in the United States during the 19th century, especially at military and public events. It was not initially the country’s only patriotic song; “Hail, Columbia” and “My Country, ’Tis of Thee” were also prominent national songs.
President Herbert Hoover signed legislation on March 3, 1931, making it the official national anthem. The huge flag Key saw flying over Fort McHenry is preserved at the Smithsonian’s National Museum of American History. That flag had 15 stars and 15 stripes, reflecting the Union’s size in 1814.