New York (CNN) -- A nearly 200-year-old copy of "The Star Spangled Banner" is set to hit the auction block Friday at Christie's auction house in Manhattan.
The famed sheet music is one of 11 known copies of Francis Scott Key's patriotic tune, said to be written after he witnessed the British naval bombardment of Fort McHenry during the war of 1812.
"This is very exciting," said Christie's spokesman Chris Coover. "Things like this are once in a lifetime to collect."
Key, then a young lawyer and amateur poet, is said to have boarded a truce vessel in the Chesapeake Bay in an effort to negotiate the release of a detained American doctor, according to documents from the Smithsonian National Museum of American History.
But Key was himself detained, the documents said.
His vantage point aboard the British ship is said to have offered sweeping views of the ensuing battle, spanning the night of September 13 to the morning of September 14, 1814.
"By the dawn's early light" Key saw that the fort's flag -- torn and burned from near constant shelling -- had remained erected above its walls, inspiring words later printed by Baltimore music publisher Thomas Carr.
Carr is said to have rushed to publish the song, leaving first copies with a typographical error in the works' title.
The copy at Christie's bears that first edition hallmark, Coover said.
The print reads: "The Star Spangled Banner. A Pariotic Song," rather than "patriotic."
The copy will be sold as a part of the auction house's autumn "Fine Printed Books and Manuscripts including Americana" sale.
It is the only privately-owned copy, Coover said.
The other 10 copies are in institutions or university libraries.
"In a sense this is a last opportunity to own a copy of the American national anthem in its first appearance," Coover said.
The copy's original owner kept the document with 49 other pieces of sheet music in an album used as a song book for family gatherings, according to Coover.
Once purchased for $50, the two-paged copy is currently valued between $200,000 and $300,000.
Congress named "The Star Spangled Banner" the country's national anthem in 1931.