The most common and most likely answer to this crossword clue is the 4 letter word IDES
I
D
E
S
More clues leading to the result IDES
- Day when one meets fate, not insignificant!
- Missing leader conceals date in Rome
- Kindness occasionally may get you a date in Rome
- Team’s cancelling southern date in Rome
- 13th or 15th, team’s heading into last place
- Very old date skins, hard leaves
- Cockney is nowhere to be seen in time of putsch
- That is finishing early one day a month
- Fish day
- . French are supporting one date, a significant date
Buddy explains!

The straight part
We know that "Caesar died on" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case caesar died on = ides.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does IDES mean?
IDES noun- (often capitalized) The notional full-moon day of a Roman month, occurring on the 15th day of the four original 31-day months (March, May, Quintilis or July, and October) and on the 13th day of all other months.
- A freshwater fish of the family Cyprinidae, found across northern Europe and Asia, especially Leuciscus idus.