Star-Spangled Banner, national anthem of the United States, approved by act of Congress on March 3, 1931. The text was written by the American lawyer and poet Francis Scott Key on board a British frigate during the British bombardment of Fort McHenry in Baltimore, Maryland, in 1814. Key had boarded the ship under a flag of truce to arrange for the release of a prisoner held by the British during the War of 1812 and had been temporarily detained during the attack. The sight of the flag still flying on the following morning inspired Key to write the poem. First printed in a handbill and then in a Baltimore newspaper, it soon became a popular song, sung to the tune of the drinking song “To Anacreon in Heaven,” which was attributed to the British composer John Stafford Smith.