Ides of March (Idus Martiae)
Beware the Ides of March --William Shakespeare, Julius Caesar, Act I Scene 2.
Beware indeed! As we all know, Julius Caesar was assassinated (Act III, Scene 1.) in the Senate House on the Ides of March of 44 B.C. Shakespeare's principal source for his play was Plutarch, a Greek writer of late in the first century of the Christian Era. In Chapter 63 of Plutarch's Life of Caesar Shakespeare read:
...a soothsayer bade him [Julius Caesar] prepare for some great danger on the Ides of March. When the day was come, Caesar, as he went to the senate met this soothsayer, and said to him by way of raillery, "The ides of March are come;" who answered him calmly, "Yes, they are come, but they are not past."
Of the number and names of all the assassins we cannot be certain. Plutarch, and other ancient writers record the following:
Within a very few years Marc Antony and Octavian Caesar, the adopted son of Julius Caesar tracked down and killed the assassins.
What are, or is, "Ides"?
The ancient Roman calendar was lunar, with each month beginning on the new moon. The Idus, or Ides, marked the time of the full moon and was so called because it divided (iduare) the month in half. By about the fifth century before Christ, the Romans fixed the months at standard lengths of 30 or 31 days, abandoning the former practice of months based on lunar observation. The Ides then was assigned to the 15th in months having 31 days and the 13th in months having 30 days. So the Ides of March simply means March 15th.
The historic association of the Ides with the full moon --regarded by all cultures as an especially portentous time-- colored the significance of the Ides even after it no longer corresponded to the astronomical event. The Romans, who never undertook any important action without first looking for some favorable omen, considered the Ides to be an auspicious time, which may be the reason the conspirators choose the Ides of March to dispatch Caesar and, they thought, to restore the Republic. However, they lacked any cohesive plan for governing; mismanaged events in the days immediately following the assassination; and ended up plunging Rome into a disastrous civil war. Peace, but not the Republic, was finally restored when, in 31 B.C., following the defeat of Antony at the battle of Actium, Caesar Octavian emerged as sole leader --the Emperor Augustus.
The Roman, Julian, and Gregorian Calendars
The Roman calendar, based on, but not precisely corresponding to, the moon, was in need of constant adjustment to keep the various religious festivals and other observances in their proper seasons. From time to time the priests would intercalate, or add months of varying lengths in an attempt to set things back to right. After a few hundred years of use it was badly in need of reform. And along came just the man to do it.
Turning afterwards his attention to the regulation of the commonwealth, he corrected the calendar, which had for some time become extremely confused, through the unwarrantable liberty which the pontiffs had taken in the article of intercalation. To such a height had this abuse proceeded, that neither the festivals designed for the harvest fell in summer, nor those for the vintage in autumn. He accommodated the year to the course of the sun, ordaining that in future it should consist of three hundred and sixty-five days without any intercalary month; and that every fourth year an intercalary day should be inserted. That the year might thenceforth commence regularly with the calends, or first of January, he inserted two months between November and December; so that the year in which this regulation was made consisted of fifteen months, including the month of intercalation, which, according to the division of time then in use, happened that year. --Suetonius, The Twelve Caesars, Life of Julius Caesar, 40.
This Julian Calendar went into effect in the year 45 B.C. and was a cause of controversy.
His reformation of the calendar, in order to rectify the irregularity of time, was not only projected with great scientific ingenuity, but was brought to its completion, and proved of very great use... Caesar called in the best philosophers and mathematicians of his time to settle the point, and out of the systems he had before him, formed a new and more exact method of correcting the calendar, which the Romans use to this day, and seem to succeed better than any nation in avoiding the errors occasioned by the inequality of the cycles. Yet even this gave offense to those who looked with an evil eye on his position, and felt oppressed by his power. Cicero, the orator, when someone in his company chanced to say, the next morning Lyra would rise, replied, "Yes, in accordance with the edict," as if even this were a matter of compulsion. --Plutarch, Life of Julius Caesar, 59.
The Julian calendar slightly over-adjusted for the difference between the true solar year and the 365-day year, and over the centuries required another adjustment, by Pope Gregory. By the time Catholic Europe switched to the Gregorian Calendar in 1582, the Julian Calendar was off by ten days; when Great Britain adopted the Gregorian Calendar in 1752 the difference was 11 days. The last Europe nation to make the switch was Greece, in 1923.
The adoption of the current custom of numbering the days of the month sequentially, and the attendant disuse of the old system of designating the days by their relation to Kalends, Nones, and Ides, came about gradually. In England, for example, both the First Prayerbook of Edward VI (1549) and the Second Prayerbook of Edward VI (1552) as well as the Authorized Version of the Scriptures (1611) contain calendars that use both systems side-by-side. Viewers of Shakespeare's play Julius Caesar (ca. 1599) would have been quite at home with his references to the Ides of March.
Things related to the Ides of March
For a list of births, deaths, festivals, and other events on March 15th throughout history and in literature, see the entry in Wikipedia.
Prior to 1955, the U.S. federal income tax filing deadline was March 15th, and served as the inspiration for a humorous essay by Robert Benchley, "On or Before March 15" which appears in Chips off the Old Benchley (Harper and Brothers, 1949), beginning on page 10.