The Ides of March
The ‘Ides’ refers to a lunar calendar, a full moon on the 15th of the month in March, May, July, and October, and the 13th in the other eight months. When the lunar calendar became different than the monthly calendar, the full moon was no longer always on the 13th or the 15th, and the phrase went out of use.
On this day in 44BC, Julius Caesar was stabbed to death by senators who called themselves the Liberatores (Liberators). They claimed they were preserving the integrity of the Roman system. In modern usage, it was Shakespeare who popularized the phrase “the ides of March” in his play Julius Caesar. Caesar is in front of a crowd of people, and he says, “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.” And a soothsayer replies, “Beware the ides of March.”