What are the Ides of March and Why Should Anyone Beware Them?

The Murder of Caesar (1865) - Karl Theodor von Piloty

The Murder of Caesar (1865) – Karl Theodor von Piloty

March 15 is the “Ides of March”, which we know from the phrase “beware the Ides of March”.  But what are “ides” and why should anyone worry about them?

Under the old Roman calendar, the Ides of March was the date of the first full moon of the year.

March was important as the first month of the year for the same reason January is important on our modern calendar. The beginning of a week, month or year always always holds some psychological (and frequently, legal) importance.

Ides was an important day because it was one of three fixed points in each month of the Roman calendar.

Kalends was the first of the month, the day of a new moon. About a week later came Nones, the day of a half moon (or the “first quarter” as you’ll usually see it on a calendar). Another week later came Ides, with the full moon.

The Romans counted towards these marker days. So March 14 would be “the day before Ides”.  March 21 would be “7 days before Kalends”.

It sounds complicated, but remember that long before there was writing, people around the world could see the moon, and could accurately predict its phases. Many of us do the same thing when we count down the days before Christmas or New Year’s Day.

(By the way, our word “calendar” comes from Kalends.)

The only person who was ever warned about the Ides of March is long-dead: Emperor Julius Caesar. Caesar was assassinated on March 15, 44 BCE.

According to Greek historian Plutarch’s biography of Caesar, a seer warned the emperor that he would come to harm by the Ides of March.

That rather vague prediction is likely to be Plutarch’s romanticized fiction, although there is historical evidence that Caesar had been warned of an impending assassination attempt, even if it were not as specific as Plutarch’s version.

The phrase we know comes from Shakespeare’s 1599 CE play about Caesar’s assassination.

More than 400 years later, the phrase is still part of our cultural landscape, although most of us think it’s a general warning about a day that is unlucky, on par with Friday the 13th.

So what are “ides” and why should anyone worry about them? They’re a bit of historical trivia that should give no one any cause for worry.