Harlequin
This is a stock character originating in Italian theater of the 17th century. It’s generally the equivalent to the court jester – a Harlequin is often a servant, known for quick wit, comedy, and getting themselves into complicated situations.
The Harlequin is usually depicted in a diamond-patterned costume, wearing a mask.
Additionally, the traditional Harlequin character had a consistent love interest: Columbina. This seems to be where the association with romance comes from – the Harlequin was always getting in various predicaments due to his pursuit of Columbina.
Why I Looked It Up
I was, of course, familiar with the term, but it was in the name of a painting by Joan Miró: The Harlequin’s Carnival. I got to wondering about the term.
I had most associated the term with the publisher of romance novels. Interestingly, I read their history page and their Wikipedia entry, and it seems that they were founded and named without any reference to the romantic aspects of the traditional Harlequin character.
Early in its history, Harlequin published inexpensive reprints of detective stories, cookbooks, westerns, and a smattering of tragic love stories.
About 10 years after it’s founding, Harlequin partnered with another publisher which was known for romance novels, which is when they drifted into that genre.
From this page called “How Harlequin Became the Most Famous Name in Romance”:
At first, the company published a mishmash of genres, with mixed success. Palmour, who ran much of the business day-to-day, noticed “nice little romances” were performing particularly well.
There’s no indication that the company ever changed its name, so its apparently just a coincidence that it was named Harlequin to start with.