Definition: On the Ides of March (or March 15), 44 B.C., Julius Caesar was assassinated, at the foot of a statue of Pompey where the Senate was meeting.
Because of the assassination of Julius Caesar and the soothsayer's exchange about it with Julius Caesar, in Shakespeare's Julius Caesar tragedy, the Ides of March now signifies a fateful day.
Before the assassination of Julius Caesar, the Ides of March was simply a division of the calendar based on the phases of the moon. In some months, the Ides is on the 15th, and in others, it is the 13th.
Examples: The source of the expression, "Beware the Ides of March":
Caesar:
Who is it in the press that calls on me?
I hear a tongue shriller than all the music
Cry "Caesar!" Speak, Caesar is turn'd to hear.Soothsayer:
Beware the ides of March.Caesar:
What man is that?Brutus:
A soothsayer bids you beware the ides of March.
Julius Caesar Act 1, scene 2, 15–19
