1. It took more than 100 years for the song to become the national anthem of the United States.Although Francis Scott Key wrote the lyrics during the Battle of Fort McHenry in Baltimore on Sept.
14, 1814, it didn’t become the national anthem until March 3, 1931. That’s when President Herbert Hoover signed a Congressional resolution officially making “The Star Spangled Banner” the national anthem of the United States.
Each March 3 now is known as National Anthem Day.2. The song wasn’t originally called “The Star Spangled Banner", and it’s actually set to a popular song from the day.According to History.com, Key specified the lyrics were intended to be sung to a song called “To Anacreon in Heaven", which ironically, was something of a British.