The ides were a way of marking days in the Roman calendar, part of a unique dating system the Romans used instead of counting days numerically like we do today.
The Roman Dating System
The Romans divided each month around three fixed points:
- Kalends (Kalendae) - the 1st day of the month
- Nones (Nonae) - the 5th or 7th day, depending on the month
- Ides (Idus) - the 13th or 15th day, depending on the month
When the Ides Fell
- In March, May, July, and October, the ides fell on the 15th
- In all other months, the ides fell on the 13th
How Romans Dated Events
Rather than saying "March 15th," Romans would count backwards from these reference points. For example:
- March 15th was simply "the Ides of March"
- March 14th was "the day before the Ides of March"
- March 10th was "five days before the Ides of March"
The Origin
The term "ides" likely comes from an Etruscan word meaning "to divide," as it roughly divided each month in half. The ides were originally connected to the full moon in Rome's early lunar calendar, though this connection was lost when the calendar was reformed.
I'm attempting to schedule a monthly event for 2026, to take place on the ides of each month. Locations and times will likely vary depending upon the day of the week on which the event is occurring. Bring stories, trackables, puzzles to solve, etc. No purchase necessary to attend.