he Ides of March (Latin: Idus Martiae) is the name of the 15th day of March in the Roman calendar, probably referring to the day of the full moon. The word Ides comes from the Latin word "Idus" and means "half division" especially in relation to a month. It is a word that was used widely in the Roman calendar indicating the approximate day that was the middle of the month. The term ides was used for the 15th day of the months of March, May, July, and October, and the 13th day of the other months. The Ides of March was a festive day dedicated to the god Mars and a military parade was usually held.
In modern times, the term Ides of March is best known as the date on which Julius Caesar was killed in 44 B.C. Caesar was stabbed (23 times) to death in the Roman Senate by a group of conspirators led by Marcus Junius Brutus and Gaius Cassius Longinus. The group included 60 other co-conspirators according to Plutarch.
According to Plutarch, a seer had foreseen that Caesar would be harmed not later than the Ides of March and on his way to the Theatre of Pompey (where he would be assassinated), Caesar met that seer and joked, "The ides of March have come", meaning to say that the prophecy had not been fulfilled, to which the seer replied "Ay, Caesar; but not gone." This meeting is famously dramatized in William Shakespeare's play Julius Caesar, when Caesar is warned by the soothsayer to "beware the Ides of March."