What Are the Ides of March? Meaning, Facts About the Day

While it's true that William Shakespeare wrote the play Julius Caesar and the famous line "Beware the Ides of March," Shakespeare did not come up with the concept of the "Ides of March." The Ides were actually established long before Shakespeare ever wrote his play.

The phrase actually refers to the date of March 15 on the Roman calendar. In the Roman calendar, the days are labeled based on what day of the month it is in correspondence with the cycle of the moon.

In the ancient Roman calendar, the first day of the month, which signifies the start of the month and begins with the new moon cycle, was always called the "Calends." The "Nones" happened on the half moon on either the fifth or seventh day of the month depending on the month, according to Time and Date. The "Ides" marked the 15th day in the months of March, May, July and October. In all of the other months, the Ides fell on the 13th day, supposedly when the full moon occurred.

Thus, the phrase "Beware the Ides of March," simply means to beware of March 15. While It wasn't until after Shakespeare wrote the phrase in his play that it became a popular one, there are some historical events that occurred on March 15 that make the day significant.

The most well-known event that happened on the Ides of March was the murder Julius Caesar by his own senators. The story goes that despite several bad omens prior to and on March 15, 44 B.C. Caesar decided to go to a meeting of the Senate anyway. There, a plan was put in motion by multiple senators to assassinate the ruler and he was stabbed repeatedly until he died.

When Shakespeare wrote his play on Caesar more than a thousand years later the warning from a soothsayer, or fortune teller, he included was "Beware the Ides of March." Thus that phrase, as well as "Et tu, Brute?" became well associated with Caesar as a historical figure as well as a theatrical one.