Why Should We "Beware the Ides of March"? Shakespeare's Historical Warning, Explained

Of all Shakespeare's contributions to the English language, there are a few phrases that have cemented themselves in pop culture. The soothsayer's famous line from the play Julius Caesar, "beware the Ides of March," has become an annual warning to citizens everywhere between March 13 and 15.

So, what are the Ides of March? And why is the soothsayer's ominous warning so important? Here's the scoop.

Since Shakespeare coined the phrase "beware the Ides of March," it seems like every other pop culture reference to the period marks the date as cursed or filled with doom. In actuality, the Ides of March had a much less threatening origin. History.com reveals that Kalends, Nones, and Ides were ancient markers used to reference dates. "Ides" refers to the first new moon of a given month, typically between the 13th and 15th.

Once, the Ides of March signified the new year, which included celebrations and revelry. However, when Julius Caesar came to power, he changed Rome's traditional New Year celebration from March to January (when the New Year is still celebrated in modern times), and two years later, he was assassinated by members of his state on March 15.

Shakespeare's play about Julius Caesar's life crafted the phrase "beware the Ides of March" about the bloody history to follow. In the play, a soothsayer attempts to warn Caesar his life is in danger and to stay home on March 15, but Caesar waves the warning off and insists he will be fine. Then, true to history, Caesar is betrayed by members of his state and literally stabbed in the back.

Today, "beware the Ides of March" is commonly used to reference ill omens or to warn people of danger (typically from within one's social circle). Numerous TV shows and films have referenced the Ides of March with Shakespeare's meaning in mind. The 2011 political drama The Ides of March, The Simpsons episode "The Ides of March," and the Party of Five episode "The Ides of March" all deal with main characters facing betrayal or other consequences for not heeding the warnings.