Here’s Why People Kiss Under the Mistletoe at Christmastime

From Harry Potter’s first kiss to Justin Bieber’s holiday tune, kissing under the mistletoe is everywhere in pop culture. But this Christmas tradition — that if you’re standing under the leafy plant, it’s time for a smooch — existed long before it ever appeared in movies and pop songs.

While historians are uncertain about why kissing under the mistletoe started, there is a general consensus regarding when and where the custom began, and how it became popular during Christmastime.

The origins of kissing under the mistletoe, a plant that often bears white berries, are often traced to a tale in Norse mythology about the god Baldur. In the story, Baldur’s mother Frigg casts a powerful magic to make sure that no plant grown on earth could be used as a weapon against her son. The one plant the spell does not reach is the mistletoe, as it does not grow out of the earth, but out of a tree’s branches. The scheming Loki, upon learning this, makes a spear out of mistletoe — the spear that would eventually kill Baldur.

But the connection between that story and the tradition is unclear, and may not even exist at all.

In many tellings, Frigg declares the mistletoe to be a symbol of love after her son’s death and promises to kiss anyone who passed underneath it. If that’s an accurate version of the story, it would be clear how it directly connects to the romantic act of today. Historian Mark Forsyth says this is not actually the way the story ends, however. Forsyth is the author of A Christmas Cornucopia: The Hidden Stories Behind Our Yuletide Traditions, and examined four Norse accounts of the god’s murder and the events that followed. “Baldur’s death involves mistletoe, but it’s got nothing to do with kissing or Christmas,” he tells TIME.

Although Forsyth does not know why kissing under the mistletoe started, the author says he does know that the tradition began between 1720 and 1784, in England.

Kissing under the mistletoe wouldn’t have existed as a popular tradition before 1720 because the most extensive research about the plant was published that year, and it did not reference the practice, Forsyth explains. John Colbatch, an English apothecary and physician, wrote two books on the mistletoe in 1719 and 1720. “He had a whole section on superstitions and customs associated with mistletoe,” Forsyth says, “and doesn’t mention anything at all about kissing under mistletoe.”

Instead, the earliest reference of kissing under the mistletoe that Forsyth found comes from a song published in a 1784. The verses read,

“What all the men, Jem, John, and Joe,

Cry, ‘What good-luck has sent ye?’

And kiss beneath the mistletoe,

The girl not turn’d of twenty.”

Other historians have also cited these lines as the first reference of the tradition. But what happened between 1720 and 1784 that made kissing under the mistletoe a holiday phenomenon remains unknown. “I can take a pretty shrewd guess that it involved a particularly lusty and inventive boy, and a particularly gullible girl,” Forsyth writes in his book.

Literature and art from the 18th and 19th centuries expanded upon this idea. Charles Dickens in The Pickwick Papers, published in 1837, portrays the holiday frenzy associated with this particular type of kiss. He writes that younger ladies “screamed and struggled, and ran into corners, and threatened and remonstrated, and did everything but leave the room, until some of the less adventurous gentlemen were on the point of desisting, when they all at once found it useless to resist any longer, and submitted to be kissed with a good grace.” In an art print from 1794, servants in a kitchen are poised for a smooch under the mistletoe, with a caption describing “Saucy Joe” who “rudely” kissed “Bridget the Cook.”

The women in both scenes were depicted as resisting the kisses but having to give in after being caught passing under the mistletoe. Historians have said that they would have believed they had to accept kisses from men or risk bad fortune. Exactly how serious the resistance was is hard to say based on documentary evidence, but Forsyth says there were several stories from the period that depicted women “using the mistletoe excuse to elude possessive husbands and parents” who might have otherwise prevented such kisses.

“A brief inspection of the ceiling would be all that it took to avoid that, whereas being forced into a loveless marriage in a world without divorce or any semblance of women’s rights would have been rather harder to escape,” he tells TIME. Noting that it is extremely difficult to decode a phenomenon two centuries later, he adds, “I can say with some certainty, though, that accidentally finding yourself under the mistletoe would have been very, very far down the list of worries and disadvantages of a woman alive in the year 1800.”

Stateside, the popularity of kissing under the mistletoe as a Christmas tradition can be more easily traced, back to Washington Irving’s The Sketch Book, which was published in 1820.

The American writer had returned from England, and recorded the yuletide traditions he had observed abroad. In the chapter named “Christmas Eve,” a footnote reads, “The mistletoe is still hung up in farm-houses and kitchens at Christmas, and the young men have the privilege of kissing the girls under it, plucking each time a berry from the bush. When the berries are all plucked the privilege ceases.”

Forsyth says that Irving’s text, a bestseller, played a huge role in accelerating the tradition’s popularity. “Christmas was only a very, very minor festival in the early 19th century,” he explains. “Irving made the template for the modern Christmas in a lot of senses.” Because kissing under the mistletoe was mentioned in The Sketch Book, a large American audience was introduced to the practice, and eventually adopted this act — and ushered it over the centuries as it went from a semi-scandalous oddity to a well-known mutual romantic gesture of holiday cheer.