Why Do We Say, 'Beware the Ides of March'?

What is the ides of March, and why do we say to "beware" it?

Mignon Fogarty
3-minute read
Episode #814
The Quick And Dirty

The ides of March is March 15. The historian Plutarch reported that a seer warned Caesar about danger around the ides of March, and Shakespeare wrote a play about Caesar that immortalized the seer's warning as "Beware the ides of March."

Around this time of year, the ominous phrase “Beware the Ides of March” starts to pop up. Beware! Beware! But what does it mean, and why should we be afraid?

The ides of March is March 15. The phrase telling us to be wary comes from Shakespeare’s play “Julius Caesar,” in which a soothsayer emerges from a crowd to warn the Roman dictator with the now-famous words: “Beware the ides of March.”

This isn’t just an act from a play either. Julius Caesar really was stabbed to death in the Roman senate by a group of senators on the ides of March in 44 BC. The ancient historian Plutarch even reported that the real-life Caesar was warned of impending doom by a seer named Spurinna, so Shakespeare was sticking pretty close to the actual history.

Caesar should have been wary of a murder plot on the ides of March.

What is the ‘ides’?

“Ides” is a Latin word of unknown origin, but it is one of three words that Romans used to mark specific days of the months on their calendar: “kalends,” “nones,” and “ides.” (And even though these words all end with S, they’re singular. The ides of March is one day.)

RELATED: Beware! The Ides of March Is (or Are?) Coming

The Roman calendar was dramatically different from what we use today. It had only 10 set months, but the Romans inserted extra months sometimes in a way I found incredibly confusing. (And it isn’t just me. The last year before their calendar was reformed is referred to as the “last year of confusion.”)

The key point for us is that their calendar was tied to the phases of the moon, and the ides was the date of the full moon and generally marked the middle of the month.

Every month had an ides, not just March. For example, the printer William Caxton referred to the ides of July in a citation in the Oxford English Dictionary from 1483, and that would have been a normal thing to do at the time, just like we’d refer to the 15th of July.

In some months, the ides was on the 13th, and in others, like March and July, it was on the 15th.

What is the ‘kalends’?

“Kalends” was the first day of the month, and it’s the origin of our modern word “calendar.”

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What is the ‘nones’?

“Nones” was the fifth or the seventh day of the month, depending on the month. It was always eight days before the ides, but the way the Romans counted it, it was nine days, which is why the name will remind you of the number nine. (They used inclusive counting, so that would be like us saying our week included Sunday, Monday, Tuesday, Wednesday, Thursday, Friday, Saturday … and Sunday again — that the week ran from Sunday to Sunday.)

According to the Oxford English Dictionary, the days after the nones were “reckoned forward to the ides,” so people would refer to a date such as October 11 as the “fifth of the ides of October” because it was five days before the ides, counting inclusively. 

What is the first month of the year?

And as an aside, it’s because of Caesar that we celebrate the new year in January. According to history.com, March 15 was the beginning of the new year on the Roman calendar, but Caesar changed it to January 1 about two years before his death as part of his major calendar reformation project, which made the calendar year more accurately match the solar year.

Beware the ides of March (and all the other ides, too)

We say “Beware the ides of March” because it’s the date Julius Caesar was murdered, and Shakespeare immortalized the phrase in his play about those events. But I think from now on, at least for me, it will mean beware having to figure out the organization and dates of the Roman calendar!

Image courtesy of Shutterstock.


About the Author

Mignon Fogarty

Mignon Fogarty is the founder of Quick and Dirty Tips and the author of seven books on language, including the New York Times bestseller "Grammar Girl's Quick and Dirty Tips for Better Writing." She is an inductee in the Podcasting Hall of Fame, and the show is a five-time winner of Best Education Podcast in the Podcast Awards. She has appeared as a guest expert on the Oprah Winfrey Show and the Today Show. Her popular LinkedIn Learning courses help people write better to communicate better.