Ides of March: What Is It? Why Do We Still Observe It?

Caesar: The ides of March are come.
Soothsayer: Aye, Caesar, but not gone.

—Julius Caesar, Act III, Scene 1

Thanks to Shakespeare's indelible dramatization, March 15—also called the Ides of March—is forever linked with the 44 B.C. assassination of Julius Caesar, and with prophecies of doom.

"That line of the soothsayer, 'Beware the ides of March,' is a pithy line, and people remember it, even if they don't know why," said Georgianna Ziegler, head of reference at Washington, D.C.'s Folger Shakespeare Library.

Until that day Julius Caesar ruled Rome. The traditional Republican government had been supplanted by a temporary dictatorship, one that Caesar very much wished to make permanent.

But Caesar's quest for power spawned a conspiracy to have him killed, and on the Ides of March, a group of prominent Romans brought him to an untimely end in the Senate House.

It Wasn't Just Caesar Who Paid the Price on Ides of March

Aside from its historical connection, the concept of the Ides of March would have resonated with English citizens in 1599, the year Shakespeare's play Julius Caesar was probably performed, Ziegler said.

"This whole business of the Ides of March and timekeeping in the play would have had a strong impact on audiences," she said.

"They were really struck by the differences between their Julian calendar [a revision of the Roman calendar created by Caesar] and the Gregorian calendar kept in Catholic countries on the continent."

Because the two calendars featured years of slightly different lengths, they had diverged significantly by the late 16th century and were several days apart.

(Related: "Leap Year: How the World Makes Up for Lost Time.")

In Roman times the Ides of March was mostly notable as a deadline for settling debts.

That calendar featured ides on the 15th in March, May, July, and October or on the 13th in the other months. The word's Latin roots mean "divide," and the date sought to split the month, originally at the rise of the full moon.

But because calendar months and the lunar cycle are slightly out of sync, this connection was soon lost.

Ides of March Assassins: Heroes or Murderers?

The Ides of March took on special significance after Caesar's assassination—but observance of the anniversary at the time varied among Roman citizens.

"How they felt depended on their political position," said Philip Freeman, a classicist at Luther College in Decorah, Iowa, and the author of Julius Caesar.

"Some were thrilled that Caesar had died, and some were horrified," he said.

The debate about Caesar's fate has extended through the ages and was taken up by some major literary figures. In Dante's Inferno, for example, Caesar is in Limbo, a relatively pleasant place in hell reserved for virtuous non-Christians.

"But Brutus [one of the leaders of the assassination] is down in the very center of hell with Judas, being munched on by Satan—it's about as bad as you can get," Freeman said.

The Folger library's Ziegler thinks the Bard had a more balanced view.

"I think Shakespeare shows both of them as being humans with their own weaknesses and strong points," she said.

Whether they were heroes or murderers, the real-life Ides of March assassins were subjected to less than pleasant outcomes.

"Within a couple of years Brutus and [fellow assassin] Cassius were dead," Freeman noted.

"They were not able to bring back the Republic, and really what they did was usher in more of a permanent dictatorship under the future Roman emperors—the opposite of what they intended."