Ides

Ides (pronounced ahydz)

(1) In the ancient Roman calendar, the fifteenth day of March, May, July, or October, and the thirteenth day of other months.  Now most associated with 15 March.

(2) A Greek plural suffix appearing in scientific names.

1300–1350: Middle English from the Old French, derived from the Classical Latin īdūs (feminine plural), the borrowing from French replacing earlier Middle English forms.  In ancient Greek, the plural of is, suffix of source or origin.  Meaning in Latin was always “middle day of a Roman month” but the origin is uncertain; some etymologists suggesting an Etruscan root although even back-formations are scant and the only evidence is īdūs was cognate with the Oscan eiduis, Oscan having many words derived from Etruscan.

The Latin practice was to treat most recurring calendrical days as plurals although both Middle English and Old French also used the singular form ide.  English use of the Roman calendrical term always employs the Romans' inclusive dating, including the ides itself when counting. Thus, the "third day before the ides of March" (a.d. iii Id. Mart.) is 13 March; two days before 15 March not three.  English usage also often follows the Latin contraction of the phrasing, which omits the words ante diem so 13 March may appear as the "third ides of March" or the "third of the ides of March". Thus, the "second ides" (pridie idus) is the fourteenth day of the old long months and the twelfth day of the other months; the "third ides" (tertia idus) is the day before that; the "fourth ides" is the day before that; and so on until the "eighth ides", which is preceded by the nones in every month.  That seems clear enough.

The Ides of March

The Ides of March is a day on the Roman calendar that corresponds to 15 March.  Several religious observances were held on the day and, like the ides of other months, was the traditional Romans deadline for settling debts.  In 44 BC, it became notorious as the date of the assassination of Julius Caesar, one of the great events of antiquity and a turning point in Roman history.

The Death of Caesar (1867) by Jean-Léon Gérôme (1824–1904).

Caesar was stabbed to death at a sitting of the Senate and it’s thought some there were some five-dozen conspirators, led by Brutus and Cassius.  In the writings of Plutarch, a soothsayer had foretold that harm would come to Caesar no later than the Ides of March. While going to the Theatre of Pompey where the Senate sat, Caesar passed the seer and joked, "The Ides of March are come", implying the prophecy had not been fulfilled, to which the seer replied "Aye, Caesar; but not gone."  In the western canon, it’s best remembered from William Shakespeare's (1564–1616)'s The Tragedy of Julius Caesar (1599), when Caesar is warned by the soothsayer to "beware the Ides of March." 

Caesar's death came at a time of crisis in Rome and unleashed the civil war from which his adopted heir Octavian (later known as Augustus) would gain power.  On the fourth anniversary of Caesar's death in 40 BC, after achieving a victory at the siege of Perugia, Octavian executed 300 senators and knights who had fought against him under Lucius Antonius, brother of Mark Antony.  The executions were the most dramatic of the things done by Octavian to avenge Caesar's death and Roman historians characterised the slaughter as a religious sacrifice, noting it happened on the Ides of March at the new altar built as a memorial to Julius.

Gretchen Wieners (Lacey Chabert (b 1982)) in Mean Girls (2004) makes the case for the murder of Caesar.