The story behind the writing of the American national anthem, now known as "The Star-Spangled Banner," revolves around the British attack on Fort McHenry in Baltimore Harbor, known as the Battle of Baltimore. Francis Scott Key, an American lawyer, penned the words on Sept. 14, 1814, after the 25-hour battle ceased, and he realized that it was the American flag, and not the flag of Britain, that was flying in victory.
A week before the Battle of Baltimore, Francis Scott Key boarded a British flagship in the Chesapeake Bay to convince soldiers to release his friend, arrested by the British. The soldiers agreed to release him, but since Key knew of the British plan to attack Baltimore, they released him back to his ship under constant guarding and scrutiny.
On Sept. 13, 1814, Key, still under guard, witnessed the onslaught of missiles, bullets and shells onto Fort McHenry. The battle continued for so long that Key began to see only red in the sky, and because the British made such a large-scale attack, he was certain of their victory. When the smoke began to clear in the early morning hours, he saw the American flag flying over Fort McHenry and began chronicling his reaction.
Key set his writing to the tune of a popular British song written by John Stafford Smith, and his brother-in-law, a Fort McHenry militia commander, distributed it under the title "Defence of Fort M'Henry." The Baltimore Patriot newspaper printed the song, which circulated in publications across the country within weeks and renamed "The Star-Spangled Banner." The U.S. Navy began using the song in 1889, and it became the national anthem on March 3, 1931, under President Herbert Hoover.