Methods of measuring time grew up about the need for determining the dates of the tabooed or holy days, and for fixing and recording the occurrence of unusual natural phenomena which were believed to have some regular significance. . . . The perfection of the methods of measuring time has been a gradual transition "from luck to mathematics." —Harry Elmer Barnes

OF ALL BIZARRE and primitive calendars, that of the early Romans reached the height of absurdity and confusion. It was an old tribal system, inherited by the legendary first ruler Romulus when he founded Rome in 753 B. C., later recorded as 1 A.U.C. (anno urbis conditae). This calendar consisted of ten lunar months, beginning with the spring moon in March and ending about 300 days later in December. The period between December and March was disregarded, being an interval of little importance because, "nothing happened" during those slumbering cold dark 60 days.

In keeping with an ancient custom the origin of which had long been lost, the months were divided into three sections known as Kalends, Nones and Ides, each of different lengths. The word Kalends, meaning a "calling" or announcement of a new month, gave us the word calendar.

Romulus lived 34 centuries after the Egyptians originated and founded their remarkable solar calendar. It is one of the ironies of history that the early Romans had no knowledge of this achievement, which eventually they had to blend into their own system, but only after many centuries of struggle with their primitive tribal heritage.

The ten-month calendar was hopeless, having none of the elements of stability and regularity that a satisfactory system of time measurement requires. Romulus did nothing about it, probably because he was without knowledge of mathematics and astronomy. His successor, Numa Pompilius, was more intelligent and scholarly, fully recognizing that the calendar needed improvement. In his long reign of 53 years he had ample time to become a constructive calendar reformer.

He increased the number of months from ten to twelve by adding January and February. The months were still lunar in character, their lengths alternating between 29 and 30 days. This gave the year 354 days but as the total was an even number and to the Romans this was unlucky, an extra 355th day was added at the end of the year.

Numa was advised by his astronomers that the extra 355th day would not be sufficient to agree with the seasons—which were important not only in agriculture but in military operations as well. To overcome this defect, Numa did what other calendar makers have done; he inserted an additional thirteenth month every two years, calling it Mercedonius (from the Latin word for wages, indicating that it meant extra remuneration). This "remunerative" month of 22 or 23 days was arbitrarily thrust into the calendar toward the end of February, after the 23rd, when the newly inserted month began. When it was finished, the remaining five or six days of February carried on. Of all the complicated man-made calendar adjustments in history, this was certainly the most fantastic.

Realizing that the awkward thirteenth month needed some authoritative supervision, Numa assigned it to the Pontifex Maximus, head of his newly created College of Pontiffs. He failed to realize that this would lead to all kinds of abuse—that the occasional 13th month would become a "political plum" which clever and unscrupulous officials could manipulate for their own purpose. By lengthening or shortening the intervals between intercalations, friends could be kept in power, enemies removed, dates advanced or postponed and all kinds of schemes promoted. And that is just what happened. Through the years such tampering with the calendar caused it to fall into chaos. The original intent to keep the calendar in line with the seasons was lost, so that in the first century B.C. the spring equinox had strayed from its place by about three months.

Meanwhile there had been other efforts which violated the calendar. About 300 B.C. a lawyer-politician named Cneius Flavius persuaded the people that all the months should have an odd number of days in order to make them lucky. February was the only exception; being the last month of the year it was unlucky, so it was shortened to 28 days. The result:

The intercalary month Mercedonius—22 or 23 days—was inserted every two years before the last five days in February to adjust the lunar year to the seasons. A Flavian cycle of four years had 355, 378, 355, and 377 days, giving an average of 366-1/4 days, or one day in excess of the seasonal year. If this had been meticulously followed from the time of Falvius to the time of Caesar, the Roman calendar would have been about 250 days out of step with the seasons, but actually the observance of the Flavian rules was irregular and indefinite, and historians have difficulty assigning correct dates to historical events in those years.

Another political interference with the calendar came in 153 B.C. when the beginning of the year was changed from the spring equinoctial date, March 25, to January 1. The new date had no scientific or seasonal significance, but was the appointed time for newly elected consuls to assume their civil duties. The populace considered this event as appropriate for the beginning of a new year so that, first by custom and later by official enactment, January 1 became the new year—a political date.

One of the incongruous results (which is still with us) was that the month named Quintilis, or "fifth" actually became the seventh month: and so with all the other numbered months—Sextilis, September, October, November and December. Romans were so keenly conscious of this absurdity that it became a pastime of the emperors to re-name the six numbered months according to their individual whims. September was known at various times as Germanicus, Antoninus and Tacitus; November was Domitianus, Faustinus and Romanus. Fortunately none of these names lasted very long.

Julius Caesar was the great reformer who made the Roman calendar the standard of the Western world. He had experienced the irregularities and difficulties of the Roman system while he was a military commander in Gaul, so that when he arrived in Rome, calendar revision was one of his chief concerns. While in Egypt, he had learned about that country's superior solar calendar, which caused him to appoint the Greek astronomer, Sosigenes of Alexandria, to be his adviser in revising the Roman system.

Caesar's authority to deal with this matter came through his election to the post of Pontifex Maximus in 63 B.C. After extensive studies, he put his new reform into effect in 45 B.C. The preceding year was one of the biennial periods which included the inserted month of Mercedonius. It became knows as the "Year of Confusion." Caesar took the 355-day year with its inserted Mercedonius of 23 days and then added two more months making it 445 days long, a drastic operation which brought the calendar into step with the seasons. (The two added months were Undecember, 33 days, and Duodecember, 34 days).

Caesar was wise in accepting without hesitation the Egyptian solar year of 12 months, with two changes. He distributed the last five days of the year (a festival period in Egypt) more evenly throughout the calendar, and he adopted Ptolemy's previously rejected extra leap-year day ("Good Doing Gods") by adding it to February every four years. The calendar was fixed at 365 days in ordinary years and 366 days in leap years. In recognition of this outstanding reform a grateful Senate honored Julius Caesar by re-naming his birth-month Quintilis, July.

As compared with the Egyptian system, Caesar's adaptation was a considerable improvement. The reduction of the intercalary period from five days every year to one day every four years lifted the Roman calendar to a new level of efficiency and convenience. It was obvious to the scholarly Sosigenes that the shorter the period of intercalation, the better the calendar.

The new leap-year day was inserted after the 23rd of February, where the 13th month of Mercedonius had been previously intercalated. Thus the 24th of February —in Roman terminology—"the 6th day before the Kalends of March"—was repeated in leap years and became a dobule-six or bissextilis. This is the origin of the term bisextile given by Europeans to the leap-year day. Speaking historically, the added day in our present leap years is actually the old "double" 24th of February—which makes the month 29 days long instead of 28.

Two Latin historians, Censorinus and Macrobius, explain the operation thus: To the old calendar of 355 days Caesar added ten days in order to make it a solar calendar. To January, March, May, Quintilis (July), Sextilis (August), October and December he gave each 31 days; and to April, June, September and November each 30 days. But February, the unlucky month of Terminalia, was left unchanged, "so that the religious rites of the gods of the nether world might not be disturbed." In this manner Caesar gave to seven months 31 days (the lucky odd number) and to four months 30 days (the unlucky even number).

The arrangement of the 31-day and 30-day months was not as regular and simple as it might have been, but presumably this did not particularly concern Caesar. We are historically quite certain that the arrangement of the months was as we have it today.

A different version of his calendar plan was published in the 1830 edition of the Encyclopedia Britannica, and gained wide currency before it was disproved many years later by the evidence of newly discovered inscriptions. This theoretical reconstruction of Roman history suggested that Julius Caesar set up an improved arrangement of the months, with alternating months of 31 days and 30 days, and that his arrangement was altered by his successor, Augustus, in order to give August as many days as July. The reason for the change, said Britannica, was Augustan vanity.

But such a foolish gesture of vanity is out of character in one of Rome's greatest and most far-sighted emperors, and the accusation against him was disproved when Italian archeologists uncovered monuments with inscriptions clearly showing that Sextilis had 31 days before it was re-named August.

Caesar did not pretend to have given the world a perfect calendar. All he claimed was that his plan was a great improvement on what had gone before. He established a solar calendar that recognized the seasons within a fixed and complete year, a worthy successor to the more ancient Egyptian solar calendar.

He did not disturb the awkward division of the months into Ides, Nones and Kalends, from which comes the old Latin-class mnemonic:

In March, July, October, May,
The Ides are on the fifteenth day,
The Nones the seventh; all the other months besides
Have two days less for Nones and Ides.

He had this latter improvement clearly in mind, but he was deterred from carrying it out because in 45 B.C. the first of January occurred on the new moon—and it was the new moon, still in high favor with a superstitious populace, that made him compromise and leave the New Year alone. Many astronomers and historians have pointed out certain advantages that would have resulted had Caesar placed the beginning of the calendar year on a really scientific basis.

Perhaps Caesar would have carried his reform further had he lived longer. He was assassinated on the Ides of March, a few months after the new calendar came into use.

During the years that followed, the unfamiliar leap-year rule was misinterpreted by the College of Pontiffs. Instead of inserting an extra day every four years, they observed leap year every three years. This caused the calendar once again to shift from its seasonal moorings, and it was Caesar's nephew, the Emperor Augustus, who undertook to correct the error. He cancelled all leap years between 8 B.C. and A.D. 8, and directed that thereafter all leap years should fall as originally intended. Once again the Roman senate gave honor to a calendar reformer by re-naming Sextilis, August, which the Emperor considered his auspicious month.

This pattern was in continuous use until it was readjusted in 1582 by Pope Gregory XIII.

CALENDAR AFTER JULIUS CAESAR