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What Is the Ides of March?

The murder of Julius Caesar. Painting by Karl von Pilaty

As spring approaches every year, the same phrase pops up again and again, repeated by those who love either Roman history or literary allusions: “Beware the ides of March!” But why? What is there to beware? What even is the ides of March?

The short version is that the ides of March is a singular date in the calendar year: March 15. But the long version goes back to antiquity, with the full explanation requiring a look at the Roman calendar, an examination of a specific event in Roman history, and, more broadly, an overview of the religious and cultural workings of Roman society.

Here’s the full story.

How the Roman Calendar Works

The Roman calendar didn’t actually number each day within the months. Instead, months were organized around three key dates and counted inclusively from one to the next. The first of these key dates were the kalends, which was essentially the first day of the month. The second was the nones, which occurred either six or four days after the kalends, depending on the month, making it either the seventh or fifth day of the month. And the third was the ides, which came eight days after the nones, making it either the 15th or 13th day of the month, depending on when the nones were counted.

The length of the month itself determined the dates of the nones and the ides. During longer months, which typically had 31 days, the nones occurred on the seventh day of the month, or six days after the kalends, while the ides happened on the 15th day of the month, eight days after the kalends. However, during shorter months—which, depending on which point in Roman history you’re looking at, could be either 29 or 30 days —the nones occurred on the fifth day of the month, or four days after the kalends, and the ides on the 13th, again eight days after the nones.

Due to the inclusive counting method used to track the days of the month, specific dates would be expressed linguistically in terms of their relationship to the kalends, nones, or ides. For example, during 31-day months, the third day of the month would typically be described as “the fifth day before the nones”; meanwhile, the 27th day of the month would be described as “the sixth day before the kalends” —the kalends, in this case, being the first day of the next month.

March, or Martius, was long considered the first month of the 10-month-long, legendary Roman calendar; January and February didn’t enter the picture until around 153 B.C.E. But throughout Roman history, March always contained 31 days, making it consistently one of the longer months. As such, the kalends occurred on March 1; the nones was marked on the seventh day of the month, six days after the kalends; and the ides happened on the 15th day of the month, eight days after the nones. We often still refer to March 15 as the ides of March today.

Beware the Ides of March

The ides of March has gone down in history as a famous date for one very particular reason: In 44 B.C.E. on the ides of March, a group of Roman senators led by Marcus Junius Brutus, Cassius Longinus, and Decimus Junius Brutus assassinated Julius Caesar.

Following Caesar’s crossing of the Rubicon river in 49 B.C.E., which started the civil war known alternately as the Great Roman Civil War and Caesar’s Civil War, the Roman Senate appointed Caesar dictator. An official, albeit temporary position, Roman dictators essentially functioned as the head of the government under times of martial law: They had enormous power but were only appointed during times of military or internal crisis, with their terms being limited to six months in length. Dictators also typically stepped down before those six months were up, resigning from the position once the crisis had passed, the government and the rule of law returned to normal, and—most importantly—an election could be held.

When Caesar was appointed dictator, he was only one of two to have taken the position since the Second Punic War, which took place between 2018 and 201 B.C.E. (The other was Lucius Cornelius Sulla, who was dictator between 82 and 81 B.C.E.) And interestingly, under these newer dictatorships, the position acted less as it had in the past and more like an entirely new office: As Britannica observes, both Sulla’s and Caesar’s dictatorships “were not for a limited emergency, but rather were meant to ‘restore the republic.'” They also had “virtually unlimited powers.”

Caesar actually resigned from the dictatorship after only 11 days—but he was appointed to the office again in 48 B.C.E, this time for a term of one year, and then again circa 46 B.C.E. for a term of 10 years. Finally, in 44 B.C.E., the Senate named him dictator perpetuo—dictator for life.

It was at this point that a faction of Roman senators, including the aforementioned Marcus Junius Brutus, Cassius Longinus, and Decimus Junius Brutus, began to worry. The concern was that, with the enormous and unlimited power he now enjoyed, Caesar was planning to overthrow the government and establish it not as a Republic, but as a monarchy, with himself as king. To prevent this from happening, they subsequently assassinated him, dramatically and publicly, at the Curia of Pompey within the Theatre of Pompey. As many as 60 conspirators stabbed Caesar 23 times with daggers which they had hidden about themselves, bringing his reign to an end.

Reenactment of Caesar's funeral procession
An annual reenactment of Julius Caesar’s funeral procession in front of the Temple of Divus Iulius in the Roman Forum Isabel Eve/Shutterstock

Although the historian Plutarch’s Life of Caesar does state that a seer warned Caesar before his assassination that harm might come to him on the ides of March, the phrase “Beware the ides of March” entered the cultural lexicon thanks to William Shakespeare. In Act I, Scene ii of Julius Caesar, which was initially performed sometime around 1599, a soothsayer urges Caesar to be cautious with the now-famous line. Caesar, however, brushes him off, saying, “He is a dreamer; let us leave him: pass.”

It’s a mistake he comes to regret.

More to the Story

The ides of March had its own significance outside of Caesar’s assassination, as well, however. For one, it was considered the deadline by which one should settle one’s debts. According to the American Institute for Roman Culture, this was likely because, according to the original Roman calendar, the ides of March was the first ides of the year-–that is, the date officially brought the previous year to an end.

Additionally, in the eras before Christianity became Rome’s official religion, the ides—all of them throughout the year—were sacred to Jupiter. As such, religious observations and celebrations occurring on or around the ides was common; indeed, a sheep was typically sacrificed to Jupiter on the ides of each month.

The ides of March, specifically, also bore witness to a few particular celebrations, including the Feast of Anna Perenna, the deity of the “circle of the year,” and possibly the festival of Mamuralia, which marked the changeover from the old year to the new. During the Roman Empire, which ran from about 27 B.C.E. to 476 C.E., Hilaria, the holy week celebrating the mother goddess Cybele also occurred around the ides of March. Both the Feast of Anna Perenna and Hilaria were typically celebrated with revelry, including much eating and drinking; Hilaria, however, involved nine days of abstinence from certain foods and drinks beforehand. Meanwhile, the authenticity of Mamuralia remains somewhat debatable—the only accounts we have of it come from much later, rather than from writings of the era in which it may have been performed—but it appears to have been more of a scapegoat ritual.

As you can see, it turns out that there’s much more to the ides of March than just one famous phrase, or even just one famous assassination. Of course, most of us probably have nothing to fear about the date itself, but it can’t hurt to exercise a little more caution than usual on March 15, right?

Lucia Peters Lucia Peters
Lucia Peters is a writer and editor based in Washington, D.C. Her work has appeared at Bustle, The Toast, Crushable, The Gloss, and others. She also writes and manages The Ghost In My Machine, where she haunts readers several times weekly with spooky stories of the strange and unusual. Her first book, Dangerous Games To Play In The Dark, was published by Chronicle Books in September of 2019. Read Full Bio »