Beware the Ides of March
The term Ides comes from the earliest Roman calendar, which organized its months around three days, each a reference point for counting the other days:
Kalends (1st day of the month)
Nones (the 7th day in March, May, July, and October; the 5th in the other months)
Ides (the 15th day in March, May, July, and October; the 13th in the other months)
The rest of the unnamed days of the month were identified by counting backwards from the Kalends, Nones, or the Ides.
So days in March would be: March 1: Kalends; March 2: VI Nones; March 3: V Nones; March 4: IV Nones; March 5: III Nones; March 6: Pridie Nones (Latin for "on the day before"); March 7: Nones; March 15: Ides.
Also: the Ides of March is the day, famously Shakespearian, when Julius Caesar was assassinated and we have centuries of feeling that, somehow, this day portends something wicked this way coming ...
Here's hoping we get through unscathed. Put on some more perfume.