Francis Scott Key wrote the poem that became the U.S. national anthem, “The Star-Spangled Banner.”
Key wrote the poem in September 1814 after watching the American flag fly over Fort McHenry during the Battle of Baltimore in the War of 1812. He had been aboard a British vessel while helping negotiate the release of American prisoners and observed the bombardment from the Chesapeake Bay.
The poem was originally titled “Defence of Fort M’Henry.” Its words were later set to the tune of “Anacreon in Heaven,” a British song associated with the Anacreontic Society. The song became increasingly popular during the nineteenth century and was adopted as the national anthem by congressional resolution in 1931.
Key was a lawyer and served as a U.S. attorney in Washington, D.C.; he was not a professional composer. The flag he saw was the large Star-Spangled Banner made by Mary Young Pickersgill, not the thirteen-star flag associated with the American Revolution.