More than any other word or phrase covered in my book Gobsmacked!: The British Invasion of American English—more than “kerfuffle,” more than “go missing,” more than “spot-on,” more than “gobsmacked” itself—the origin of “easy peasy” is shrouded in mystery, or, at least, uncertainty.

For starters, most British people’s belief that it came from an advertising slogan for Sqezy dishwashing liquid, “Easy Peasy, Lemon Sqezy,” is Mandela-effect-level flat-out wrong. The language historian Barry Popik and Pascal Tréguer, who runs the Word Histories blog, have both established that there was never such a slogan. Rather, from 1957 until 1962, the product’s tagline was “It’s Easy with Sqezy.” Shortly after that, the brand was discontinued. It wasn’t until two decades later that the first instance of the full phrase was spotted (by Tréguer), in a 1983 article in The Guardian: “Chap comes in, sits down, says, ‘I want to be a marine biologist.’ Easy peezy lemon squeezy.”

As to why people reverse-engineered this slogan, the trochaic-tetrameter rhythm is appealing. And the fact that there are other lemon-scented dish detergents made the idea that Sqezy might have offered one plausible.

Another odd thing about the phrase, at least in its two-word version, is its nationality. Google’s nifty Ngram Viewer tool, which charts an expression’s frequency of use over time (and can handily break down its use in British versus American books), confirms it’s what I call a “Not One-Off Britishism,” meaning that it originated across the pond—in this case in the late 1970s—and migrated to the U.S. some two decades later.

A graph traces the usage of “easy peasy” in Britain and the U.S. over the past 40 years.

Yet The Oxford English Dictionary cites three uses way before the 70s, and two of them come from American sources. The first is very early and not American: in a 1923 article about traditional mummers’ plays (i.e., folk plays performed by amateur actors), there is a reference to “The Berkshire Doctor’s cure of the ‘easy-peasy, palsy, and the gout.’” And in the 1940 American film Long Voyage Home, the character played by John Wayne says, “Easy-peasy. Take it easy, Drisc!” A 1953 article in The Cincinnati Enquirer, meanwhile, noted, “There’s a brief air travelogue of highlights of a jet trip from London to Cairo…. The flight is such an easy-peasy affair for the air travellers, they seem to be motionless in a fantastic and lovely, sun-drenched cloudland.”

My guess would be that, in all three cases, the phrase was used not because it was in circulation but because the rhyme came easily to the tongue. The same is true of the other popular variant, “Easy peasy, Japanesey,” which Popik spotted in 1982 (that is, a year earlier than the “Lemon Sqezy/Squeezy” version). The character played by James Whitmore uses the phrase in the 1994 film The Shawshank Redemption, set decades earlier.

The first time “easy peasy” was used in The New York Times by an American (the writer Patricia Marx) was in 2006. Since then, the phrase has been in the paper or on its affiliated sites 83 times, 7 times this year alone. A memorable appearance was in a 2012 article about a New York City burglar: “The following morning, he was awakened by police officers in his bedroom. One of them said, ‘Easy, peasy, lemon squeezy,’ first handcuffing, then dressing” him.

While the phrase is clearly out and about in the U.S., it’s not common enough to be a target for parody. It is in Britain, where, in Armando Iannucci’s 2009 satire In the Loop, a U.K. politician says to his American counterpart, “In England we have a saying for a situation such as this, which is that it’s ‘Difficult difficult lemon difficult.’”

Ben Yagoda is professor emeritus of English at the University of Delaware and the author of several books. He runs a blog called Not One-Off Britishism