Congress officially adopted “The Star-Spangled Banner” as the U.S. national anthem on March 3, 1931.
The song’s words originated in Francis Scott Key’s poem “Defence of Fort M’Henry,” written after he watched the British bombardment of Fort McHenry during the Battle of Baltimore in the War of 1812. Key wrote the poem on September 14, 1814, after seeing the large American flag still flying over the fort.
The melody was adapted from “The Anacreontic Song,” a British tune associated with the Anacreontic Society and composer John Stafford Smith. The song became popular in the United States long before it received official national status. The U.S. Navy recognized it for official use in 1889.
Congress passed the national-anthem resolution on March 3, 1931, and President Herbert Hoover signed it the following day. The anthem officially contains four stanzas, although public performances usually sing only the first.