BEWARE....

...THE IDES OF MARCH.

The following story, too, is told by many. A certain seer warned Caesar to be on his guard against a great peril on the day of the month of March which the Romans call the Ides; and when the day had come and Caesar was on his way to the senate-house, he greeted the seer with a jest and said: “Well, the Ides of March are come,” and the seer said to him softly: “Ay, they are come, but they are not gone.”

— Plutarch, The Life of Julius Caesar.

And by day's end Caesar was assassinated by a group of Senators.

The ancient Romans gave us our basic calendar, but they did not number the days as we do, but rather counted down to three days fixed within each month: the Nones, Kalends, and Ides.

The Ides (Latin: idus “half division”) is the 15^th day of the month of March, May, July, and October, and on the 13^th otherwise. In the very early days of Rome, the Ides was the day of the full moon (and considered auspicious), but it was quickly changed into a fixed day within each month. But the Ides of March was not auspicious for Caesar, nor for the Roman Republic.

The first day of the month was the Kalends (where we get our word calendar) and originally was the day of the new moon.

Halfway between Kalends and Ides was Nones, the day of the half-moon, and traditionally a market day.  Nones was the 7^th day of the month in March, May, July, and October, and the 5^th otherwise.

As mentioned, the Romans numbered the days of the month by counting down to each of these days.

For example, today, the 15^th of March, is Idus Martius, or Id. Mart.

Yesterday the 14^th was Pridie Idus Martius, or Prid. Id. Mart.

Other days are counted down: the 13^th is ante diem III Idus Martius, or a.d. III Id. Mart.; the 12^th is a.d. IV Id. Mart.

Please note how they count: just as when we tell of Jesus' three days in the tomb, we count Good Friday as day 1 and Easter as day 3, likewise the Romans counted the Ides as day 1.

Continuing to the beginning of the month:

March 11^th — a.d. V Id. Mart.
March 10^th — a.d. VI Id. Mart.
March 9^th — a.d. VII Id. Mart.
March 8^th — a.d. VIII Id. Mart.
March 7^th — Nones Martius
March 6^th — Prid. Non. Mart.
March 5^th — a.d. III Non. Mart.
March 4^th — a.d IV Non. Mart.
March 3^rd — a.d. V Non. Mart.
March 2^nd — a.d. VI Non. Mart.
March 1^st — Kalends Martius

Dates after the Ides count down to the Kalends, or first day, of April.

March 31^st — Prid. Kal. Aprilis

March 30^th — a.d. III Kal. Apr.

March 29^th — a.d. IV Kal. Apr.

March 28^th — a.d V Kal. Apr.

and so on.

The early Roman calendar had other oddities, such as leap months instead of leap year days, as well as calendar reforms which led to changes in dates.

For examples of Roman dating, please see this photo of the tomb of the Venerable Felix de Andreis, at Saint Mary of the Barrens Church in Perryville, Missouri:

I leave the translation of the dates as an exercise to my readers!

See also my post on the vernal equinox.