"Beware the Ides of March!"
Do you recall this quote?
Most of us associate the "Ides of March" as bad luck because it's depicted in movies and described in modern books as a day to tread lightly and be on high alert for bad luck, but probably most notable is William Shakespeare's play, Julius Caesar. Caesar was assassinated on March 15th.
But did you know that the Ides of March wasn't always considered unlucky? Matter of fact it was even met with celebration because it was a day of many religious observations. It was also the deadline of settling debts in Rome.
Where did this does this idea of "ides" originate and what is it?
The Roman calendar was based on the lunar calendar. Each month a cycle of the moon occurs. Around the 1st of the month the New Moon occurs. This happens when the moon is directly between the sun and the Earth. Imagine you're in a pitch black room. Directly in front of you, on the opposite side of the room a flashlight is illuminated. There is an object directly between you and the flashlight. You can only see the outline of the object in front of you. This is similar to the New Moon phase.
The Full Moon phase is when you can see the entirety of the moon. Now in the dark room, the flashlight and the unknown object are on opposite sides. You are directly between them. Turn yourself away from the light and towards the unknown object. As the flashlight is illuminated, this is like the Full Moon phase. The time after the New Moon but before the Full Moon is called Waxing. This is the time more and more of the moon begins to show at night leading up to the Full Moon. The time after the Full Moon and before the New Moon is called Waning. This is the time when the moon begins to show less and less each night.
Now that we have a general understanding about the lunar phases the Roman calendar will be a little easier to understand.
They didn't count the days like we do today. Instead they used three definitive markers in each month: Kalends, Nones, and Ides. The Kalends was the New Moon date, or the first day of the month. The Ides was the Full Moon date which was the 13th of every month, except in March, May, July, October. For those months, the Ides was the 15th day. The Nones was after the Kalends and before the Ides. It was the 7th of 9th day of the month.
So if they didn't use numbered days, how did they know what day it was? The easiest way to explain this is they used chunks of time to explain what day it was. For instance, March 5th would be considered "before the Nones," March 12th would be "after the Nones," and any day after the Ides (March 15th) would be "before the Kalends."
Lastly, remember the Roman calendar only had 10 months, beginning with March. This explains September starts with sept, meaning seven, October starts with oct, meaning eight, and so on. So March 15th was the first full moon of the new year which was cause for celebration!
Side note, if you're superstitious, the full moon for March 2022 isn't actually today. It's on Friday the 18th, which is even more reason to celebrate the Ides instead of bewaring them!