You've probably heard the soothsayer’s warning to Julius Caesar in William Shakespeare's play of the same name: “Beware the Ides of March.” Not only did Shakespeare’s words stick, but they also branded the phrase—and the date, March 15—with a dark and gloomy connotation.

It’s likely that many people who use the phrase today don’t know its true origin. In fact, just about every pop culture reference to the Ides—save for those appearing in actual history-based books, movies or television specials—makes it seem like the day itself is cursed.

The Ides of March actually has a non-threatening history. Kalends, Nones and Ides were ancient markers used to reference dates in relation to lunar phases. Ides simply referred to the first full moon of a given month. Since the Roman calendar was based on lunar cycles, a full moon usually fell between the 13th and 15th. In fact, the Ides of March once signified the new year, which meant celebrations and rejoicing. Because calendar months and lunar months were different lengths, they quickly got out of step.

Yet when heroes in movies, books and television shows are faced with the Ides of March, it’s always a bad omen. Several television shows have had episodes named “The Ides of March.” And it’s never good news.

In 1995 alone, the Ides-related episode of “Party of Five” was based around a cocaine-related death and featured a near-incident involving drunk driving; “Xena: Warrior Princess” had its protagonist facing threats from an ominous vision that showed her and her travel partner, Gabrielle, put to death by crucifixion; and Homer Simpson’s rise to power within the ancient secret society known as the Stonecutters in The Simpsons episode “Homer the Great” leads to his self-proclamation as a God. In warning him of his inevitable downfall, Lisa plays the part of the soothsayer, quoting “Beware the Ides of March.” Homer simply says “No,” and laughs it off (much like Caesar did in the play) but, like Caesar, he soon experiences a swift undoing.

In 2011, Columbia Pictures released The Ides of March, a movie about an idealistic campaign staffer (Ryan Gosling) who gets a harsh lesson in dirty politics while working for an up-and-coming presidential candidate (George Clooney). The movie involves quite a bit of figurative backstabbing, but it’s a pretty clear allegory for the death of Caesar. Again, death and destruction loom.

Did the death of Caesar curse the day, or was it just Shakespeare’s mastery of language that forever darkened an otherwise normal box on the calendar? If you look through history, you can certainly find enough horrible things that happened on March 15, but is it a case of life imitating art? Or art imitating life?

Perhaps it was Julius Caesar himself (and not the famous playwright) who caused all the drama. After all, he’s the one who uprooted Rome’s New Year celebration from their traditional March 15 date to January…just two years before he was betrayed and butchered by members of the Roman senate.