I bought a bag of York peppermint patties yesterday for Christmas and, having recently visited York, wondered if there was any connection to the English city.
The name does come from the location, but not the location I visited — the patties were originally produced in York, Pennsylvania, USA in 1940. (I suppose you could say there is a connection in the sense that York, PA was probably named after York, UK.) The candies even used to be called “Yorkshire Peppermint Patties.” (Later, production was moved to Reading, PA, which was probably named after Reading, UK as well.)
When and where did the idea of putting mint flavor in candies originate? In fact, the York Peppermint Pattie’s connection to England may be deeper than namesake. Although peppermint itself had been used as an herbal remedy long before Europeans discovered the herb — earliest accounts of mint (“Mint-of-the-Mountains”) usage date back to 1500 B.C. in Egypt, for headaches and other ailments , and mint drinks were popular in the ancient Middle East — the idea of mixing peppermint flavor with sugar, and marketing it as a sweetmeat rather than a medicine, seems to come from the English.
In ancient times, before sugarcane spread throughout the world, honey was used to make sweets. The Persians (and later the Greeks, when Alexander the Great invaded Persia) brought sugarcane, “the reed which gives honey without bees,” from South Asia to Central Asia and Europe around 510-330 B.C. 
In medieval Europe, sugar was initially used as an additive in apothecaries’ herbal medicines. Early accounts of herbal treatments include comfits , whole spices and seeds covered in sugar. Spearmint, Mentha spicata (the name of which derives from the plant’s “spear”-shaped leaves), was first described in the English language in London herbalist John Gerard’s 1597 book Herball, or General Historie of Plantes. Carolus Linnaeus, father of binomial nomenclature, first described the peppermint plant, Mentha x piperita, in his 1753 book, Species Plantarum, although he incorrectly identified peppermint as a species: it is actually a hybrid between spearmint (Mentha spicata) and watermint (Mentha aquatica).
In 1780, in London, England, Altoids mints were developed by Smith Kendon Ltd. and sold in chemists’ shops to relieve intestinal discomfort.  Presumably, distillation and purification techniques enabled chemists to extract essential oils from mint plants and give mints like altoids their “curiously strong” flavor. People must have found such remedies tasty — and gradually, perhaps in tandem with both (1) discoveries of more effective modern medical drugs that made herbal remedies obsolete and (2) British colonial expansion to the West Indies, which poured tons of sugar into Britain starting in the 1700s (thanks to slave (and later indentured servant) labor on sugarcane plantations) — peppermints transitioned from the domain of chemist to confectioner in England.
The Thompson family was one such group of confectioners. They made sweets from their home town of Kendal, Cumbria, England in the early 1800s. In 1869, young Joseph Wiper married into the Thompson family and began working for their confectionery business. Supposedly, while boiling sugar for glacier mints, he accidentally left the solution overnight and it became cloudy and grainy. They poured out the mixture to let it harden, found it tasted good, and Kendal “Mint Cake” was born. 
Kendal Mint Cake was made from sugar, glucose, and peppermint oil and was anything but cake: it was very thin, dense, and hard and broke into pieces cleanly. (In fact, Kendal Mint Cake was so unlike cake that customs officers in New York, upon inspecting a shipment from England in the 1950s, ruled that “cake” should have flour in it and ordered it dumped in the sea instead of granted entry into the U.S.) At first the mint cake was sold locally.
Several confectionaries besides Wiper’s sprung up in the area, including Quiggin’s, now the oldest surviving mint cake manufacturer — Daniel Quiggin, son of a confectioner in Isle of Man, moved to Kendal in 1880 and opened a mint cake factory. (Wiper’s business was bought by Romney’s in 1987. Romney’s, which still exists along with Quiggin’s, was founded by Sam Clarke in 1914 and is named after celebrated Kendal portrait painter George Romney.)  
Robert Wiper, Joseph Wiper’s great-nephew, took over the Wiper family business in 1912 and cleverly marketed mint cake as an energy food, and it became popular amongst mountaineers and military troops.  A shipment of mint cake accompanied Sir Ernest Shackleton’s ill-fated Trans-Antarctic Expedition, but the real international acclaim came after Edmund Hillary and Tenzing Norgay requested the snack from Romney’s for their expedition to Mt. Everest in May 1953. After Hillary and Norgay became the first men to reach the summit, Hillary recounted, “we had a good look around at the world spread like a map below…we drank sweetened lemonade and nibbled mint cake as we sat there picking out places.”  
Thanks to the Everest expedition, Mint Cake became popular amongst expeditions around the world, from Nepal to Alaska . Back in England, Kendal Mint Cake became the snack of choice for hikers in the Lake District. I saw Kendal Mint Cake for sale when I visited the Lake District last summer and picked up a bar (knowing nothing about its history) because I saw it was advertised as being from “Lakeland,” the name of my hometown in FL. (I was amused that I had found Lakeland in the UK — although again, it’s possible that my town was named after this region in England.)
Traditionally, three varieties of mint cake have been made: white, brown, and chocolate-covered. The chocolate-covered variety looks very similar to a York Peppermint Pattie.
Chocolate-covered Kendal Mint Cake vs. York Peppermint Pattie
Presumably, the tradition of making peppermint sweets spread to the US from England. Henry C. Kessler first produced the York Peppermint Pattie in 1940, right as Mint Cake started to achieve its international acclaim. Chocolate-covered peppermint candies existed in the US before Kessler’s invention, but most were “gooey and soft” — perhaps more akin to a “peppermint cream”, which has Scottish/Celtic roots. Kessler wanted his version to be anything but gooey — it had to pass the “snap test”: “if it didn’t break clean down the middle, it wasn’t packaged for sale.”  This hardness feature is uncannily similar to mint cake. Had Henry C. Kessler received his inspiration for cool and crisp mint patties from Kendal Mint Cake? Possibly, but I’ve found scant documented evidence.
Kessler’s York, PA business, just as the Kendal mint cake businesses, remained local for several years. National distribution of the patties didn’t begin until 1975, after the company was acquired by Peter Paul. The patty was acquired by Hershey Foods in 1988. 
Following this meandering and incomplete history of mint confectionery makes me wonder what other foods have interesting histories behind them. What events have led us to eat what we eat now? How has culture/language/availability of technologies like paper and printing affected what foods we do know a lot about (i.e. that most of the documentation of mint and sugar recipes comes from English pamphlets?) and may misguide our attribution of origin? Fascinating, but difficult to trace.
A few sidenotes
- Residents of (the original) York, UK make their own version of a mint cake — “Yorkshire mint pasties,” a mixture of mint, brown sugar, and currants baked in a turnover.
- February 11 is National Peppermint Patty Day.
- Here’s a recipe for mint cake if you’d like to try making it yourself.
- Another recipe I’d love to try is “Sugar of Roses.”
Sources / Notes
 Joachim, Henry, translator. The Papyrus Ebers. Translated from the German version by Cyril P. Bryan. Ares Publishers Inc.: Chicago, 1974. https://hdl.handle.net/2027/coo.31924073200077?urlappend=%3Bseq=70
 Bishop, Holley. Robbing the Bees: A Biography of Honey. Free Press: New York, 2005. https://goo.gl/FBuoQF
 “Comfit.” Merriam-Webster Dictionary. https://www.merriam-webster.com/dictionary/comfit
 “Altoids Facts and History.” http://www.wrigley.com/ea/brands/altoids.aspx
 Holman, Tom. A Lake District Miscellany. Frances Lincoln: London, 2007. https://goo.gl/24bUCm
 “Kendal – The Old Yards.” Visit Cumbria. https://www.visitcumbria.com/sl/kendal-yards/
 “The History of Romney’s.” Romney’s. https://www.mintcake.co.uk/history-of-romneys-mint-cake/
 See Advertisement for Robert Wiper’s Original Kendal Mint Cake as it appears in the Old Cumbria Gazetteer, 1926. http://www.geog.port.ac.uk/webmap/thelakes/html/lgaz/pr1665.htm
 Side note: Hillary and Norgay stayed at the summit all of 20 minutes, as oxygen supplies were limited. The subheading of that article: “Stayed 20 Minutes Taking Pictures and Eating Cake and Drinking Lemonade.” I don’t think people reading realized that “cake” meant hardened tablet of mint-flavored sugar and the “lemonade” was a hot lemon drink.
 “HILLARY RECOUNTS EVEREST ASSAULT: New Zealander Tells of 5-Hour Climb With Tenzing to Gain World’s Highest Peak.” New York Times (1923-Current file), Jul 03, 1953, pp. 21, ProQuest Historical Newspapers: The New York Times with Index, https://search-proquest-com.gate3.library.lse.ac.uk/docview/112775349?accountid=9630.
 Kinloch, J. D. “The Dietary Intake and Activities of an Alaskan Mountaineering Expedition.” British Journal of Nutrition, vol. 13, no. 1, 1959, pp. 85–99.
 “About Us.” York. https://www.hersheys.com/york/en_us/about.html
 McClure, Jim. “York Peppermint Patties: ‘York became synonymous with dark chocolate and peppermint.'” 29 Jul 2009. http://www.yorkblog.com/yorktownsquare/2009/07/29/paconeco/