in 2014.
"But they know just one thing about him.
"There was a lot more to the man than just that he wrote 'The Star-Spangled Banner' under dramatic circumstances."
Key writes in the third verse of his historic poem that the "foul footsteps" of slaves who fought with the British have polluted America.
"My students really struggled with that line," author and former teacher Karsonya Wise Whitehead told The Baltimore Sun in 2014.
What are the lyrics for The Star-Spangled Banner?
Only the first of four stanzas is usually performed:
"O say can you see, by the dawn's early light,
What so proudly we hail'd at the twilight's last gleaming,
Whose broad stripes and bright stars through the perilous fight
O'er the ramparts we watched were so gallantly streaming?
And the rocket's red glare, the bomb bursting in air,
Gave proof through the night that our flag was still there,
O say does that star-spangled banner yet wave
O'er the land of the free and the home of the brave?"
When did The Star-Spangled Banner Become the National Anthem?
The song was made the national anthem in 1931 when Congress passed a measure declaring it so.
It had been recognized for official use by the US Navy in 1889, and by President Woodrow Wilson in 1916.
Over the years there have been many memorable performances, including by Whitney Houston at the 1991 Super Bowl.
Others have famously botched the song, including actress and comic Roseanne Barr.
In recent years NFL quarterback Colin Kaepernick and other athletes have kneeled in protest during the national anthem to protest racial inequality and injustice in the US.
Kaepernick to play for.