The Ides of March (Latin: Idus Martii or Idus Martiae) is the name of the 15th day of March in the Roman calendar.
The word Ides comes from the Latin word "idus", 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. Another point which arises is Shakespeare's use of the Ides of March and (the lack of doubt in) Marcus Brutus' decision to assassinate Caesar to portray an atmosphere of madness, pleasure, and pandemonium. It is said that on ides of March the sea succumbs to chaos and the full moon brings high tides. All these points give the Ides of March a very mysterious quality.Via http://ancientpeoples.tumblr.com/post/29828393657/the-ides-of-march-latin-idus-martii-or-idus