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(Wednesday, September 14, 1814; during the Battle of Baltimore, part of the War of 1812) — American lawyer Francis Scott Key was inspired to begin writing the poem “Defence of Fort McHenry” (later “The Star-Spangled Banner,” the U.S. national anthem) today after witnessing how an American flag flying over the Maryland fort had withstood a night of bombardment by the British Royal Navy during the Battle of Baltimore in the War of 1812.

Key was inspired by the large U.S. flag, with 15 stars and 15 stripes, known as the Star-Spangled Banner, flying triumphantly above the fort after the battle.

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The poem was set to the tune of a popular British song written by John Stafford Smith for the Anacreontic Society, a social club in London. Smiths’ song, “To Anacreon in Heaven” (or “The Anacreontic Song”), with various lyrics, was already popular in the United States.

This setting, renamed “The Star-Spangled Banner,” soon became a popular patriotic song.

“The Star-Spangled Banner” was first recognized for official use by the United States Navy in 1889.

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On March 3, 1931, the U.S. Congress passed a joint resolution making the song the official national anthem of the United States, which President Herbert Hoover signed into law.

It has become controversial in the United States since the 1990s due to perceived racism in the anthem’s lyrics and Key’s involvement in slavery.