On this Day, March 3, 1931, Francis Scott Key's song The Star-Spangled Banner is adopted as the American national anthem by Congress.

But how that happened exactly is little-known to most. To put it simply, it was an evolution and a process...but to put it mildly, it was not at all simple.

Of course, Key wrote the song in 1814 after seeing the American flag flying following the British bombardment of Ft. McHenry during the War of 1812.

But in writing the song, Key borrowed widely from other songs and melodies, often with very similar lyrics.

Long assumed to have originated as a drinking song, the melody was taken from the song “To Anacreon in Heaven,” which first surfaced about 1776 as a club anthem of the Anacreontic Society, an amateur mens’ music club in London. Written by British composer John Stafford Smith—whose identity was discovered only in the 1970s by a librarian in the music division of the Library of Congress—the song was sung to signal a transition between the e