When the soothsayer warned Caesar, “beware the Ides of March,” it certainly was an ominous statement, full of dread. But what exactly are the Ides? Are they really that sinister?
As it turns out—unless you’re Caesar—they’re not. “Ides of March” was simply the standard way of saying “March 15” in Roman times. In fact, the Ides of March is just one of twelve Ides that appear every year. The term “Ides” come from the earliest Roman calendar which is said to have been created by Romulus, the mythical creator of Rome. The calendar centered each month around three days; these were used as a point of reference for counting the other days. The three days were:
Kalends—the 1st of the month
Nones—the 7th day of the month in March, May, July, and October; the 5th day in the other months
Ides—the 15th day of the month in March, May, July, and October; the 13th in the other months.
The rest of the days of the month, all of which were unnamed (except for Pridie Nones, Latin for “on the day before”) were figured out by counting backward from the named days (the named day was included in the count). So, for example:
March 7: Nones
March 8: VIII Ides
March 9: VII Ides
March 10: VI Ides
March 11: V Ides
March 12: IV Ides
March 13: III Ides
March 14: Pridie Ides
March 15: Ides
It is hard to believe, but this incredibly confusing calendar system was used all the way through the Middle Ages and well into the Renaissance.