Chances are, you’ve seen the phrase “Keep Calm and Carry On” (or parodies ranging from “Keep Calm And Call Batman” to the Harry Potter-inspired “Keep Calm And Harry On”) emblazoned across everything from t-shirts to tea towels. The expression stems from a series of bright-red motivational posters produced by the UK's Ministry of Information in 1939 to boost public morale during World War II.

Now, The Guardian reports, you can purchase the real thing: An original print of the WWII-era poster—the one that initially launched its worldwide popularity—went up for sale this week at Olympia's Art & Antiques Fair, an annual event held in London’s Kensington Olympia Exhibition Centre. There, British modern art vendor Manning Fine Arts is expected to sell the print for £21,250 (about $28,000) before the fair's end on July 3.

If you’re wondering how a simple poster could fetch such big bucks, it’s because it’s surprisingly rare. The Ministry reportedly produced around 2,500,000 copies of the poster in its first print run, along with two more designs that read “Your Courage, Your Cheerfulness, Your Resolution Will Bring Us Victory” and “Freedom Is in Peril. Defend It With All Your Might.” The other posters were hung across Britain, but it’s said that officials worried that the “Keep Calm” prints were too obvious or patronizing, and they were never officially issued. Stocks of the posters were held in reserve, then eventually pulped and recycled in a 1940 paper salvage drive.

Nobody quite knows how many of the optimistic prints remain today, but in 2000, a man named Stuart Manley, who owns Barter Books in Alnwick, Northumberland, found a surviving "Keep Calm And Carry On" print at the bottom of a box of old books. Manley and his wife framed it, and they began selling reproductions to admiring customers. Over the next decade, it became a worldwide phenomenon.

Now, Manley’s famous poster is finally up for purchase. To learn more about this rare piece of wartime memorabilia, watch a short film about its history and design in the video above. 

[h/t The Guardian]

Banner image: Wikimedia Commons // Public Domain

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