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Frequently Asked Questions

How were years numbered before the time of Christ?

In many ways. Each nation had its own method of numbering years. Early Romans counted them from the City of Rome’s founding, which corresponds to what we now refer to as 753 B.C. Greeks numbered every four years as one Olympiad, starting with the first Olympic games in 776 B.C. Many other nations started counting years over again with each new ruler, so they would refer to the (n)th year of king whoever. Another widely used method was to count them starting with some important event. For instance, the caliph Omar, who succeeded Mohammed as the leader of Islam, established a year count starting from the time of Mohammed’s migration from Makkah to Medina in A.D. 622.

When did the use of A.D. and B.C. begin?

A.D. is an abbreviation of the term anno Domini, Latin for “in the year of the Lord.” The concept of A.D. is thought to have been first used in the 6th century by Dionysius Exiguus, a monk. This era began with what most people think was the year of Christ’s birth. (Some historians now say that Christ was born from 4 to 7 years earlier.) The term B.C. for “Before Christ” has been in use since the end of the eighteenth century. Neither of these two eras start with a year numbered as zero: 1 B.C. is followed immediately by A.D. 1.
Note that a.d. (in lower case) stands for ante diem, a term once used when naming a day in terms of its relation to either the Calends, Nones or Ides in early Roman calendars. Example: “a.d.VI.Kal.Mar.” referred to the sixth day before the Calends of March.

What were months of September, October, November & December named after?

See the answer to “Why do the 9th thru 12th months have names that mean 7th, 8th, 9th and 10th?” immediately below.

Why does February have only 28 days?

January and February both date from shortly after the time of Rome’s founding. They were added to a calendar that had been divided into ten month-like periods whose lengths varied from 20 to 35 or more days. Those lengths are believed to have been intended to reflect growth stages of crops and cattle. The winter season was not included.
When introduced, January was given 29 days and put at the beginning of the calendar year. February was given 23 days and put at the end. Then, for an undetermined period shortly after Rome’s founding, months were said to have begun when a new moon was first sighted. At some later time, month lengths were separated from lunations and again became fixed. At that time, February’s original length was extended by five days to give it a total of 28. If you would like to read about other nations that also added five days to their calendars close to the same time see my 8th to 4th Century B.C. Calendar Changes.

Did the new millennium begin on January 1 of 2000 or 2001?   

Both! A millennium is any period of one thousand years. One in which all year numbers have a high order (thousands) digit of 2 began with the year 2000 and will end at the close of 2999.
Because the A.D. era’s first year was numbered one, the first thousand years of that millennium ended at the close of year 1000. The next A.D. millennium began with 1001 and ended a thousand years later at the end of 2000. So the third A.D. millennium began at the first moment of 2001.

Will you please tell me (whatever) for my homework?  

If I helped everyone who asked me to provide information for homework I would have time for nothing else. Some time ago I quit responding to all those email requests. (If you are looking for detailed data about Caesar and/or Rome rather than calendars, you should visit both N.S. Gill’s Julius Caesar and Bill Thayer’s RomanSites).

How frequently do dates of a calendar year repeat on the same days of the week?  

In terms of all dates of two calendar years being on corresponding days of the week, identical Gregorian Calendar leap years repeat after every 28 years as long as every fourth one of them includes a 29-day February. Common years are different—they repeat after either six, eleven or 28 years, but these repetitions are broken after a fourth year that is not intercalary. You can check it out using links provided in the following question’s answer.

What formula can be used to associate dates with a day of the week?  

There are several to choose from at Rudy Limeback’s Calendar Links (chlick this link)

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Sunday was named after the Sun. Monday was named after the moon.
This page explains why the week has seven days and how each of them got its name.

A long time ago in human history, people thought that Earth was flat, and at the universe’s center. They believed that seven members of the solar system forever circled around us—see graphic to the right, or view one from Censorinus – Sur le jour natal.
Some Mediterranian peoples also believed that each hour of the day was ruled by either the Sun, Moon or one of five then-known planets, all of which were thought of as gods. The sequence in which they thought hours were governed was the inverse order of distance they believed those solar system objects to be from Earth.

During this time, Egyptians thought that the most distant was Saturn, shown at the bottom of the graphic above. They thought that the order of closer members (shown counterclockwise following Saturn) was Jupiter, Mars, Sun, Venus, Mercury and closest, the Moon. So they believed that the first hour was ruled by Saturn, the second by Jupiter and so on. ¹
Egyptians also believed that after each seven hours the order in which these objects ruled was repeated, so it started again with Saturn.
According to those ancient Egyptians, the planet that ruled the first hour also governed the entire twenty-four hour period, and gave its name to that day. ²   The first (and also the 8th, 15th and 22nd) hours of the first day were sacred to Saturn, the 23rd to Jupiter, the 24th to Mars and the first hour of the next day to the Sun. Therefore, they believed that the first day was ruled by and named after Saturn (Saturday) and the second was ruled by (and named after) the Sun (Sunday). ³

Celsus claimed that the same doctrine was part of ‘Persian theology.’ ⁴ Six hundred years ago, Chaucer described this belief in his Treatise on the Astrolabe under the heading of Special declaracioun of the houres of planetes.⁵ Chaucer’s text was translated from a much earlier manuscript from Greece.
The distance that these sky gods were perceived to be from Earth is not the same as the order in which they were believed to have ruled days. This is easy to understand but difficult to visualize. If you care to see it shown in the form of a chart, select Hourly Cycle that Determined Day Names.
Egyptians once divided all twelve 30-day months (of their 360-day calendar year) into three 10-day weeks in the same manner as Greeks of the same period. ⁶   The epoch at which planet worship caused them to change its length to seven days is not known, but it must have been over twenty-five hundred years ago because Herodotus, writing in his History during the 5th century B.C. said: “Here are some other discoveries of the Egyptians. They find…each day belongs to a god…” ⁷
Adherents of the cult of Sin at Harran, who were known as Harranians or Sabeans by Arabic and Syrian authors, named their days after the same solar system members 8 as Egyptians and Persians. Like Hebrews and many other peoples, they considered the one named after Saturn to be the seventh day, so they began their week with a day named after the Sun. All seven days were named after solar system members in the same order as they were in Egypt.
Constantine
It is interesting to note that these exact same solar system objects, and in the same sequence, were also used to name days in ancient India, Tibet and Burma. 9   This is also true of names for Japanese days of the week, but the custom there has been traced back only a thousand years. ¹⁰
Roman soldiers stationed in Egypt became accustomed to the pagan seven-day week and began to introduce it into their own homeland to replace their eight-day marketing week. Octavian (Caesar Augustus) and succeeding Roman rulers permitted this practice but it wasn’t made official until the emperor Constantine took that step in A.D. 321.
English names for days of the week are derived from Anglo-Saxon names for those same seven heavenly bodies that were revered by ancient peoples. Compare those English and Anglo-Saxon day names in the table below. Other similarities between day and “planet” names in various countries can be observed there.

Solar System Objects and Some of Their Various Day or “Planet” Names

Note the German day name of “Mittwoch” instead of “Mercury Day.” This came about because sometime around A.D. 1020 a Monk named Notker coined the term in mittauuechun (in the middle of the week) as a substitute for using the pagan god Mercury’s name. ¹²
There’s an alternate explanation for how the same heavenly objects came to be used to name days of the week in their present order. It assumes that the sequence of hours dedicated to these sky gods resulted from the length of their orbital periods in Earth-days. ¹³ But this would have required using Earth’s year in place of a value for the Sun, and lunation’s instead of the Moon’s yearly period. It also requires “planetary leaps,” skipping two planets at a time when assigning day names, all very improbable procedures.

REFERENCES:

1. Macrone, Michael. By Jove! New York: Cader Books, 1992. pp. 209-211.
2. Catholic Encyclopedia: SUNDAY (8KB)
3. Macrone. op. cit., p. 210.
4. Bickerman, Elias Joseph. Chronology of the Ancient World.
Ithica, N.Y.: Cornell University Press, 1968. p. 59.
5. Chaucer, Geoffrey. A Treatise on the Astrolabe. (81KB). c. 1391. Part II-12.
or Special Declaracioun of the Houres of Planetes. (2KB).
6. Goudsmit, Samuel A. Time.
New York, Time Incorporated, 1966. p. 24.
7. Herodotus. The History. (5th century B.C.) 2.82.
8. Langdon, Stephen Herbert. The Mythology of all Races: Semitic.
New York: Cooper Square Publishers, Inc., 1964. p. 154.
9. Parise, Frank. The Book of Calendars.New York: Facts On File, Inc. p. 172.
10. Renshaw, Steven L. The Solar System and Names for Days.
11. Renshaw, Steven L. ibid.
12. Borst, Arno. The Ordering of Time.
Chicago: The University of Chicago Press, 1993. pp. 60-61.
13. Zerubavel, Eviatar. The Seven Day Circle.
Chicago: The University of Chicago Press, 1985. pp. 14-17.

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Our Gregorian Calendar—which has more or less succeeded in its primary objective of keeping in phase with seasons—has received a great deal of criticism. Many organizational problems are caused, both in scheduling and period to period comparisons, because its calendar months, quarters and years all begin on various days of the week. As a result, most annual events experience a change in either day of the week or date in the month from one year to the next.
Many people have advocated the use of a perennial calendar (one that is the same every year) to overcome this situation. But changing to a good perennial calendar has its own problems. That’s because solar year length is just over 365.24 days. Some method of dealing with that uneven number would be necessary in order for each yearly event to always occur on both the same day of the week and date of the month in all years, common and intercalary.

Calendar designers have resorted to various means, some of which appear to be more successful than others in working around the year’s uneven number of days. Here are some techniques used, together with links to calendar designs incorporating them:

• Add a 13th month – Bonavian Leap-Month and Cotsworth.
• Two days are not part of any week or month – World and Tolkein’s Shire.
• Extend some day lengths (beyond 24 hours) – Long-Sabbath.
• Intercalary weeks – New Millennium.
• Two different week lengths – Fixed-Week

All of the above types of calendar modification have both advantages and disadvantages over each of the other kinds. If you would like to compare their features you should view A Perennial Calendar Comparison.

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Julian Calendar, the prior page in this series, told how Julius Caesar revised the Roman calendar so it would keep more closely in phase with seasons. Soon after the first Caesar’s assassination, his nephew and adopted son Octavian, shown to the right, became the emperor that we refer to as “Augustus.”

For the first four decades after Julius Caesar’s death, leap years had been incorrectly observed every third year instead of every fourth. It is believed that Octavian corrected this error by eliminating intercalation for 12 years. The claim is that leap years were discontinued from about 9 B.C. until sometime in the first decade of this era.
Some also claim that the month of Sextilis was lengthened and renamed for Augustus by the consuls Gaius Asinius Gallus and Gaius Marcius Censorinus who served as Ordinary Consuls of the Roman Republic in 8 B.C.E.
Except for varying lengths of months and quarters, the revised Julian calendar served its users well for a long time. However, adding an extra day every four years resulted in extending the calendar over eleven minutes beyond the seasons every year. This was not perceived as a problem for hundreds of years, but by the middle of the sixteenth century of this era, these added minutes had accumulated to point that Christian festivals were not being observed during their original seasons.
This problem had been known and discussed for several centuries, but the Julian Calendar was not revised further until the time of Pope Gregory, near the end of this era’s sixteenth century. You can read about changes made then that resulted in our present Gregorian Calendar.

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The Julian Calendar’s intercalation rule called for an extra day in February every four years without exception. This provided for almost eight more intercalary days than necessary in each thousand years. As a result, the calendar continued to became further out of phase with seasons as time passed by. As early as the thirteenth century of this era, Roger Bacon and others pointed out that some calendar change was needed, but nothing was done for many years to correct it.
     By the mid sixteenth century, actual moon phases were occurring four days prior to those in ecclesiastical tables, so Easter was sometimes being celebrated prior to the vernal equinox rather than following it as had been specified by the A.D. 325 Council of Nicaea. A decree on fasts and feast days that addressed this problem was approved in A.D. 1563 at the Council of Trent.

According to the Trent council, two main things needed to be accomplished regarding the calendar: reestablish the vernal equinox date to not occur much later than March 21 and determine the Easter moon’s 14th day. Easter would then be observed on the following Sunday. Following some of the council’s recommendations, Pope Pius V modified both the intercalation rule and lunar tables used to determine Easter’s date.
Pius V’s successor was Pope Gregory XIII, who had been a representative of Paul III at the Trent Council. Aloysius Lilius and others urged Gregory to complete the Trent recommendations. In Gregory’s tenth year this step was taken. Lilius, considered to be principal author of the Gregorian Calendar, had proposed that the seasonal error should be corrected by dropping ten intercalations during the following forty years. This was apparently based on his observation that vernal equinoxes then occurred on March 11.
Others, including mathematician and astronomer Christopher Clavius (shown on the left) agreed with the ten-day correction but believed that they should be dropped all at once. Gregory took this advice and shortened October of A.D. 1582 by ten days. Thursday, October 4, 1582 (Julian) was followed immediately by Friday, October 15, 1582 (Gregorian).
Gregory completed modification of the old intercalation rule by specifying that any year whose number ended with 00 must also be evenly divisible by 400 in order to have a 29-day February. He also changed the ecclesiastical table of moon phases used to help determine Easter’s date.
Regardless of these improvements to the formula and table values used, and because lunations are out of sync with Earth’s revolution around the sun, Easter is observed in some years during March and others in April.
Except for predominently Catholic countries, nations were slow in adopting Gregory’s changes. For a list of nations and the dates they adopted the Gregorian Calendar see this page. Among the last European power to accept it was Great Britain. That empire and its colonies (including those in America) put it into effect in 1752. By then, in order to stay in sync with nations that had already adopted Gregory’s changes, the switch involved eliminating eleven days from the old Julian Calendar. At the same time, they changed the beginning of their legal year from March 25 to January 1.
Because of Gregory’s refinement of the leap year rule, our Western calendar has almost kept pace with seasons.
As time goes by, correspondence between seasons and Gregorian Calendar dates vary, and tend to become further removed. This is because Gregory’s leap year rule is a rigid formula whose calculated results do not match year lengths over extended periods of time. One way to keep the calendar more closely coordinated with seasons over the long term is to use a method that is based on observation. This can be done with A Generalized Leap Year Rule.

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   Early Romans sometimes inserted a 22 or 23-day month into their calendar after the 23rd day of Februarius. Called either Mercedinus or Intercalaris, its purpose was to keep holidays in their historical place within the solar year. However, for political or other reasons, by the time of Julius Caesar that month was being observed only now and then—not every second year as was originally intended. Because of this, by 46 B.C. holidays no longer occurred during the same season as they had near the time of Rome’s founding.

In order to return festivals to their original position, Caesar extended that calendar year to a total of between 443 and 445 days, depending upon which historian one believes. ¹   Many modern historians have accepted the figure of 445 days for 46 B.C., that so-called “year of confusion.” Caesar, taking advice from an astronomer named Sosigenes, eliminated the month of Intercalaris and assigned all months other than February either 30 or 31 days. This extended future calendar year lengths to 365 days in common years and (by adding an extra day every fourth year) 366 in leap years. These changes resulted in the new Julian Calendar which converted their old nominally lunar calendar to one that was truly solar.
It’s sometimes said that Caesar’s new calendar was copied from the Alexandrian, but the only Alexandrian feature copied was its average year length of 365.25 days. ²
Romans began using their new Julian Calendar in 45 B.C. with what some sources claim was a leap year. But this belief that 45 B.C. was not a common year is probably untrue. A leap year should not have been needed because it followed the year of confusion, whose length had been extended the number of days required to put future calendars into a desired relationship with religious holidays.
Caesar had intended that during every succeeding fourth year an extra calendar day beyond the 365 in common years would be observed. It is believed that for about four decades after Caesars’ death, priests in charge of the calendar erroneously inserted an extra day every three years instead of every four. If true, this would have caused calendar dates to slowly drift away from their original seasons.

Soon after the first Caesar’s assassination, his nephew and adopted son Octavian, shown to the right, became the emperor that we refer to as “Augustus.” According to the fifth-century Roman writer Macrobius, the 3-year leap year mixup happened but was corrected by Augustus who eliminated intercalation for a period of 12 years.

Some claim the month of Sextilis was renamed for Augustus by Gaius Asinius Gallus and Gaius Marcius Censorinus who served as Ordinary Consuls of the Roman Republic in 8 B.C.E. Possibly they also extended that month’s length from what had been 30 to 31 days at the same time by reducing the length of another month by one day.
The revised Julian calendar served its users well for a long time. However, adding an extra day every four years resulted in extending the calendar over eleven minutes beyond solar year length every calendar year. This was not perceived as a problem for hundreds of years, but by the middle of the sixteenth century of this era, these added minutes had accumulated to point that Christian festivals were not being observed during their original time frames.
This problem had been known and discussed for several centuries, but the Julian Calendar was not revised further until the time of Pope Gregory, near the end of this era’s sixteenth century. You can read about changes made then that resulted in our present Gregorian Calendar.
Don’t confuse the Julian Calendar with Julian Numbers. They are two completely different things. See Calendrical Terms for a definition of the latter.

FOOTNOTES:
(1) Kepler, Johan. Letter to Herwart. A.D. 1597
(2) The Alexandrian Calendar had twelve months, each 30 days in length, in Julius Caesar’s time. In order to keep that calendar in phase with the solar year, 5 “epagomenal” days were observed after the twelfth month in three out of each four years. Every fourth year, 6 epagomenal days were added rather than 5.

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Much of the knowledge we now have about early Roman calendars came from Ovid, a Roman born in 43 B.C., and from Plutarch, a Greek biographer who wrote between A.D. 105 and 115.¹   Both of them had access to historical documents that are no longer extant. Ovid claimed that his information was “dug up in archaic calendars,” ² so it was already ancient over two thousand years ago.
We can assume that Rome’s original citizens brought from their birthplace the notion of calendars having ten major divisions because early-on theirs contained only ten months. It has been suggested that those month lengths reflected growth cycles of crops and cattle. When compared with the solar year, it had an uncounted winter period of approximately sixty days.

Plutarch pointed out that months at the time of Rome’s founding were of varying lengths, some as short as twenty days and others with thirty-five or more in what early Romans believed was a year of three hundred and sixty days. ³  Read more about his comments at Plutarch on the Early Roman Calendar.
Romulus, the legendary first Roman king, was said to have made extensive changes to those month lengths, assigning twenty-nine days to some and thirty-one to others. If you are interested in legends, you might want to read Romulus in Mythology.
Both Ovid and Plutarch made it clear that Martius, originally the first month, was named after Mars, the Roman god of war. Six of the other original ten were simply numbered as Quintilis thru Decembris (fifth thru tenth) but there were already disagreements when Ovid wrote, two thousand years ago, as to the sources of names for what were originally the second thru fourth, Aprilis, Maius and Junius. These disagreements continue to the present time.
When writing about April, Ovid said “I have come to the fourth month, full of honor for you; Venus, you know both the poet and the month are yours.” ⁴ Someone later pointed out that “April was sacred to Venus, and her festival–the Festum Veneris and Fortuna Virilis–occurred on the first day of this month.” Apparently Aprilis stems from aphrilis, corrupted from Aphrodite, a Greek name for Venus. Jakob Grimm, a later authority, opposed this stating it may have originated from the name of a god or hero named Aper or Aprus.” ⁵
Maius was said by some to be named after the goddess Maia, a daughter of Atlas, and Junius “is indirectly named after the goddess Juno, the Roman equivalent of Frigga.” ⁶ But Ovid suggested that names of months we now call May and June possibly refer not to sky-gods but rather to elders and young men. ⁷
The original fifth month, Quintilis, received the name of Julius (July) to honor Julius Caesar. And the original sixth, Sextilis, was named Augustus in honor of the second Caesar. The original seventh thru tenth months retained their names (Septembris, Octobris, Novembris and Decembris) but thru time became the nineth thru twelfth months.
There was disagreement even in Ovid’s day as to the sequence and time at which Januarius and Februarius were added to the original ten months.
Januarius probably became part of the calendar about half a century after the time Rome was founded because Plutarch said that Numa, the king who followed Romulus, made it the first month of the year and made February the last. One historian assigns that action an exact date by stating that “January and February were added to an original Roman calendar of only ten months in 713 B.C.” ⁸
January was named after Janus, a sky-god who was ancient even at the time of Rome’s founding. Ovid quoted Janus as saying “The ancients called me chaos, for a being from of old am I.” After describing the world’s creation, he again quoted Janus: “It was then that I, till that time a mere ball, a shapeless lump, assumed the face and members of a god.” Numa honored Janus by founding a temple for him. ⁹ That may have been the reason Plutarch assumed Numa added January to the calendar.
Some say Februarius got its name from a goatskin thong called a februa (“means of purification.”) On the 15th day of this month Romans observed the festival of Lupercalia. During the festival, a februa was wielded by priests who used it to beat women in the belief that it would make a barren woman fertile. However, there’s a Latin verb februare, meaning to “expiate” or “purify.” It seems more reasonable to assume the purification people had in mind when naming the month was that of the calendar year’s length, not that of women upon whom the thong was applied.
Apparently Februarius, when adopted, had but 23 days—traditionally the 23rd day of that month was the end of the calendar year.¹⁰   That indicates Februarius may have been observed in pre-Romulan times when months had as few as twenty days. Also, adding five days at year-end (to extend February’s length to 28) is similar to the change made by many other peoples who, around the time of Rome’s founding, added five days to their own calendar, but considered them to be unlucky and not part of the normal year.¹¹

Romans always reconciled differences between calendar and solar year lengths during that “Month of Purification.” Whenever and however Roman calendars were modified to correspond to year length, it was always done after the 23rd day of February, traditionally the last day of the year. Even in our time, leap year is observed with a 29-day February. To purists, “leap day” is February 24, not the 29th.
Plutarch wrote: “Numa…added an intercalary month, to follow February, consisting of twenty-two days, and called by the Romans the month Mercedinus. This amendment, however, itself, in course of time, came to need other amendments.” ¹² (When observed, that leap month always immediately followed February 23.)
Here’s what the historian Livy said about Numa’s contribution to the Roman Calendar:

“First of all he divided the year into twelve months, corresponding to the moon’s revolutions. But as the moon does not complete thirty days in each month, and so there are fewer days in the lunar year than in that measured by the course of the sun, he interpolated intercalary months and so arranged them that every twentieth year the days should coincide with the same position of the sun as when they started, the whole twenty years being thus complete. He also established a distinction between the days on which legal business could be transacted and those on which it could not, because it would sometimes be advisable that there should be no business transacted with the people.” ¹³
Others claim that it wasn’t until 452 B.C. that a month named Intercalaris was added to the Roman calendar in order to add those days required to bring calendar length back into phase with the solar year. This month also began after the 23rd day of Februarius. It was observed every second year and was said to have had a length of either 22 or 23 days, with the remaining five days of Februarius added after them. ¹⁴

Shown on the right is a Roman Calendar wall painting for the months of Januarius, Februarius and Martius. It was created at a time January and February were the first two months of the year. Each day in their eight-day marketing week is identified by one of the letters A thru H listed vertically on the far left side of each month’s column.
On the top line between day letter and abbreviation for month name is a “k•,” short for kalendae, the name Romans gave the first day of each month. You can see that the first day of January was identified with the letter A. Special days were indicated by red letters including an A for the first day of each eight day period or an N or other letter in addition to the day letter for some other days. This may well be the source of our own term “Red Letter Days.”
Note that the last day of January is labeled E and the first day of February continues the weekly cycle with an F. Similarly, the last day of February is an A and the first day of March is labeled B.
Roman Numerals for 29, 28 and 31 at the bottom of the painting indicate the number of days in those first three months of the Roman Republican Calendar.
In 45 B.C., Romans modified their method of marking time to keep it in phase with seasons, but not require intercalation of an extra month. They accomplished this with the Julian Calendar. Month lengths were extended to bring the calendar’s total to 365 days, making it truly solar. This change was accompanied by addition of an extra day every fourth year (after February 23rd) because of the almost six extra hours beyond 365 days in a tropical year.
For additiional information about the early Roman calendar see Bill Thayer´s Calendarium.

FOOTNOTES
(1) Grant, Michael. The Ancient Historians.
New York: Barnes & Noble Books, 1994. p. 310.
(2) Ovid. Fasti. (Roman Holidays) Translated by Betty Rose Nagle.
Indiana University Press. Bloomington & Indianapolis. 1995. 1.7
(3) Plutarch. Numa Pompilius.
8th-7th Century B.C. Translated by John Dryden.
(4) Ovid op. cit., 4.13-14.
(5) Krythe, Maymie R.
All about the Months. New York:
Harper & Row, Publishers, 1966. p. 88-89, 102-103.
(6) Macrone, Michael. It’s Greek to Me!- Brush up
your Classics. New York: Cader Books, 1991. p. 211.
(7) Ovid op. cit., 5.73-78.
(8) Thom, Irving Looking at Calendars
(9) Livy History 1.19
(10) Kowalski, Wladyslaw Jan. February 23rd.
(11) Parise, Frank, Editor. The Book of Calendars.
New York: Facts On File, Inc.
(12) Plutarch op. cit.
(13) Livius, Titus. (Livy) The History of Rome. Vol. I, Section 1.19.
(14) Bickerman, Elias Joseph. Chronology of the Ancient World.
Ithica, N.Y.: Cornell University Press, 1968. p. 43.

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Imagine you are a juror in an unusual trial. It is now more than half completed. Prosecuting attorneys have rested their case against the defendant who was charged with misrepresentation by making this claim:

“For a period during historical times the solar year contained twelve lunar cycles that averaged 30 days, resulting in a total length of 360 days for both twelve lunations and the solar year.”

Expert witnesses for the prosecution said that both angular momentum and the second law of thermodynamics precludes such a possibility. This seemed to confirm what you have always believed—that for the entire period of human history, the year was, like it is now, a little longer than 365 days. You are ready to find the defendant guilty. But please wait for the defense to present its case! Your opinion could be swayed by evidence that follows. Will you see to it that justice is served?
Defense witnesses are, or were, real people. Of course, none of them were at the fictional trial related here. But testimony is from their written works, none of which were composed to support the defendant’s point of view. Footnotes give book, chapter and verse.
For his first witness, the defense attorney has just called the historian Plutarch, who lived in the first century of this era.

Question: “In The Life of Numa you wrote about Roman history and irregularity of months in their early calendar. What were lengths of lunations and the year believed to be when Rome was founded?”

Plutarch: “…during the reign of Romulus…(they) held to this principle only, that the year should consist of three hundred and sixty days.” (1)
(You can quickly look at a footnote by clicking on its reference number. Then, to return to the footnoted text, press your browser’s Back button.)

Q. “Please tell us about five days being subtracted from twelve of the moon’s periods and then added to the solar year’s 360-day length.”

Plutarch: “They say that the Sun, when he became aware of Rhea’s intercourse with Cronus, invoked a curse upon her that she should not give birth to a child in any month or year; but Hermes, being enamoured of the goddess, consorted with her. Later, playing at draughts with the moon, he won from her the seventieth part of each of her periods of illumination, and from all the winnings he composed five days, and intercalated them as an addition to the three hundred and sixty days.” (2)
Q. “Thank you, sir. For the jury’s sake, let me point out that—using Plutarch’s figures—a seventieth of twelve 30 day lunations would be five days and a fraction. That amount of time subtracted from 360 days results in a little over 354 days, the same as twelve present lunations. When added to 360, it is identical to current solar year length!
“Plutarch’s testimony seems to confirm my clients belief that the solar year was previously 360 days—identical with the number of days then in twelve lunations.
“I now call Samuel A. Goudsmit to the stand. Mr. Goudsmit, you wrote a book titled Time. In it you state that early Egyptians began their year when the star Sirius was seen to come over the eastern horizon just before sunrise. Was that the only way they marked the passing of time?”

Goudsmit: “They also kept a separate year made up of 12 fixed 30-day months…Later, to make their lunar year jibe almost precisely with Sirius’ rising, they tacked five extra days onto the year.” (3)
Q. “Where did Egyptians think these days came from?”Goudsmit: “To account for them they created the myth of Nut, the sky goddess, who had been unfaithful to her husband, Re, the sun god. In retribution, Re decreed that she should bear a child ‘in no month of no year.’ But Nut’s lover Thoth played dice with the moon and won five days a year. Because these days were outside the calendar, Re’s decree did not apply. Nut’s son was born on the first of them.” (4)
At this the prosecuting attorney jumped to his feet and shouted:

“Your honor, this is the second fairy tale that has been told by a defense witness. We can’t allow that kind of evidence to be introduced into this trial.”
The judge agreed, saying “The defense will confine its case to factual information.”
Q. “Certainly, your honor. But isn’t it interesting that the myth we just heard parallels the story told by Plutarch? In both accounts the moon gambled and lost. As a result, five days were subtracted from twelve lunations and added to the solar year’s length.
“I now call Thomas Key to the witness stand. How did the Romans treat those extra five days, Mr. Key?”

Key: “So completely were these five days considered by the Romans to be something extraneous, that the soldier appears to have received pay only for 360 days.” (5)
“That seems to confirm Plutarch’s statement that Romans in Romulus’ time considered the year to be only 360 days in length. I now call Frank Parise to the witness stand. Tell us, Mr. Parise, in The Book of Calendars that you edited, what was said about the older Egyptian 360-day calendar year changing to one of 365 days?”
Parise: “This 360 day calendar, like so many others, was changed during the 8th century B.C. to one of 365 days. The extra five days was simply added to the end of the year.” (6)
Q. “Mr. Parise, is it true that the Chinese Zodiac is based on 360 degrees just like the one used in the west?”Parise: “The number of degrees…does not add up to 360 because in the 4th century B.C. the Chinese astrologers suddenly changed the division of the circle from 360 degrees to 365 degrees 15 minutes.” (7)
Q. “That would indicate earlier Chinese believed the yearly circle contained 360 days, but by the 4th century B.C. came to grips with the fact that it was then about 365.25 days.

“Ladies and gentlemen of the jury, prosecution argued that because 360 is such a nice, round number, early peoples used it instead of actual year length as a measure of the year’s span. But shortening the calendar to some arbitrary number of days is contrary to its primary purpose. (8)
“My client maintains that when calendars had only 360 days in their year, a lunation was approximately 30 days, and twelve of them almost exactly matched a solar year’s length. This contention is supported by all of the defense witness statements we have heard including Mr. Parise’s comment about Chinese astrologers changing the number of degrees they consider to be present in the year’s circle.
“We now call Robert H. Dott, Jr. to the stand. Mr. Dott, you and Roger L. Batten wrote the book titled Evolution of the Earth. In it you describe the study of growth rings in fossil materials and claim that they provide values for the number of days in the year at the time they were formed. Who did the original studies on corals?”

Dott: “Professor John Wells of Cornell University.” (9)
Q. “I understand that ‘modern’ is the term used in your field to refer to the past few millennia. How many lines per year did Professor Wells find on modern corals?”

Dott: “on average… 360 lines per year.” (10)
Q. “Thank you, sir. No further questions. Defense calls Mr. L.E. Doggett to the stand. Mr. Doggett, you wrote extensively about calendars. Will you please tell the court about the unusual manner in which religious calendars on the Indian sub-continent divide their months into lunar days?”

Doggett: “Lunations are divided into 30 tithis, or lunar days. Each tithi is defined by the time required for the longitude of the Moon to increase by 12° over the longitude of the Sun. Thus the length of a tithi may vary from about 20 hours to nearly 27 hours.” (11)
Q. “Let’s see if I understand this. They divide the 360 degrees in a circle by twelve degrees and the result is 30. So it seems that the twelve degree arc of a tithi is designed to make the length of every lunation 30 days, in spite of the fact that the mean lunar period is now about 29.53 days.
“Tell us, Mr. Doggett, how do they reconcile the 30 tithis with actual lunar cycles?”

Doggett: “During the waxing phases, tithis are counted from 1 to 15 with the designation Sukla. Tithis for the waning phases are designated Krsna and are again counted from 1 to 15. Each day is assigned the number of the tithi in effect at sunrise. Occasionally a short tithi will begin after sunrise and be completed before the next sunrise. Similarly a long tithi may span two sunrises. In the former case, a number is omitted from the day count. In the latter, a day number is carried over to a second day.” (12)
Q. “So there are 30 tithis in every lunation. This devious procedure is obviously an attempt to reconcile observed lengths of lunar cycles with those that averaged 30 days for a time during the B.C. era as my client claims. Do they have a similar arrangement for solar months?

Doggett:”A solar month is defined as the interval required for the Sun’s apparent longitude to increase 30º, corresponding to the passage of the Sun through a zodiacal sign (rasi). The initial month of the year, Vaisakha, begins when the true longitude of the Sun is 23º 15′. Because the Earth’s orbit is elliptical, the lengths of the months vary from 29.2 to 31.2 days.” (13)
Q. “So the Indian religious calendar’s solar month is also divided into 30 parts! By these actions, Indians can observe holy days in their original time frame, assuming they originated when lunations lasted 30 days.
“Our next witness is Elias Joseph Bickerman. Mr. Bickerman, you wrote a book about calendars that is now in the reference section of many libraries. How well did nations in the first millennium B.C. succeed in modeling months and the year in their calendars?”

Bickerman: “All the ancient calendars before the Julian year (except for the late Babylonian 19-year cycle) were inadequate. They diverged from the sun, disagreed with the moon, and…differed one from another.” (14)
Q. “This would indicate either that early civilizations were grossly incompetent in the simple task of measuring the length of lunar cycles and the year, or that the time for both moon and Earth to complete their orbits changed after those calendars were created. Did any early historian comment about this?”

Bickerman: “Censorinus, writing in 238, when Julian time-reckoning had already been accepted by the majority of Greek cities, explains the disarray of pre-Julian lunisolar calendars by uncertainty concerning the actual duration of the solar year.” (15)
Q. “Thank you Mr. Bickerman. The ‘uncertainty’ Censorinus wrote of may well be explained by changes in year lengths between the time of 360 day calendars and that of Julius Caesar. My client has suggested that there may have been one or more intermediate year lengths between those of approximately 360 and 365.24 days.
“I now call the Biblical author Enoch to the stand.

Q. “Please tell us, sir, about the year’s length.”

Enoch: “In 3 years there are 1,092 days, and in 5 years 1,820 days, so that in 8 years there are 2,912 days.” (16)
Q. “That indicates you believed solar year length to be 364 days during your lifetime. Thank you, sir! I now call John P. Pratt, Meridian Magazine contributor, to the stand. Mr. Pratt, I understand that you specialize in both religious chronology and ancient calendars. Was Enoch the only person in his area and time frame who believed that the calendar should reflect a year length of 364 days?”

Pratt: “Both the Qumran Calendar described in the Dead Sea Scrolls and also the calendar of the Book of Jubilees had 364 days.” (17)
Q. “Thank you Mr. Pratt. Apparently Enoch wasn’t the only person who witnessed a 364-day year. Now I call Herodotus, father of history, to the stand. Please tell us sir, how well did the Egyptian calendar match seasons in what we now know as the fourth century B.C.?”

Herodotus: “Egyptians, by allotting thirty days apiece to each of the twelve months (and adding five days outside of the number in each year), make the cycle of the seasons come out to the same point as the calendar.” (18)
Q. “Now, will you please tell the court about the Trojan breastplate described in your third book?”

Herodotus: “The breastplate was of linen and with many figures woven into it, and decorated with gold and cotton embroidery. The greatest wonder of it is that each single fine thread of the fabric has in itself three hundred and sixty strands, and they all can be seen to be there. One exactly like it was dedicated by Amasis, in Lindus, to Athena.” (19)
Q. “I point out to the jury that Athena is a name used in Homer’s Odyssey for an astronomical object that some consider to have been the planet Venus. Homer implied it had an interaction with the moon and Mars. If it interacted with the moon, it also affected the Earth and could have been the agent that changed lengths of lunations and the solar year.

Q. “Your honor, with your permission I’ll introduce this terra cotta slab into evidence. Jurors may view it at An Ancient 360-day Calendar. Defense rests its case.”

Prosecution Summary:
“Ladies and Gentlemen of the jury, we all know that science today is far advanced from its state during the first millennium B.C. Scientific testimony for the prosecution has shown that in historical times neither the moon’s period nor that of the year could have changed by the length of time claimed by the defense. Do your duty and find the defendant guilty of misrepresentation.”

Defense Summary:
“You have heard testimony from both historical figures and modern calendar authorities that clearly call into question the belief that lunar cycles and solar years were always the same lengths as we observe them to be today. What else but some prior time when twelve lunations whose average was about 30 days—almost matching a 360-day solar year—would have caused peoples all around the world to take actions and make statements such as you have heard today in this trial?”

Judge’s Instructions to the Jury:
“Jury members will consider only evidence given in this trial. Any preconceived notions should not influence your decision. Please go into the jury room and submit your vote to the foreman.”

Now it’s your chance to express an opinion. How do you find the defendant? You can express any comments or merely vote by sending email to: wrrh@charter.net

FOOTNOTES:
(1) Plutarch. (c.  A.D. 75)   Translated by Bernadotte Perrin. Lives, The Life of Numa.
(2) Plutarch. Isis and Osiris. Section 12 (c.  A.D. 80) Translated by Frank C. Babbit.
In Section 44 of the same work Plutarch states: “Then again, the Moon herself obscures the Sun and causes solar eclipses, always on the thirtieth of the month;” This would be the case only if each calendar month started on the day a new lunar crescent could first be sighted, and lunations were a full 30 days in length.
(3) Goudsmit, Samuel A. Time. New York: Time Incorporated, 1966. p. 69.
(4) Goudsmit, Samuel A. ibid., p. 69.
(5) Key, Thomas Hewitt   Calendarium
(6) Parise, Frank. Editor. The Book of Calendars. New York: Facts On File, Inc. p. 126.
(7) Parise, Frank. ibid., p. 217.
(8) Goudsmit. op. cit. p. 55
(9) Dott, Robert H. Jr., Roger L. Batten. Evolution of the Earth. New York, NY. 1981. p. 288. (10)
(10) Dott, Robert H. Jr., Roger L. Batten. ibid., p. 210.
(11) Doggett, L.E.   Calendars.   Sausalito, California 94965: University Science Books.
(12) Doggett, L.E.   ibid.
(13) Doggett, L.E.   ibid.
(14) Bickerman, Elias Joseph. Chronology of the Ancient World.Ithica, NY:
Cornell University Press, 1968. p. 210.
(15) Censorinus.   de Die Natali.
(16) Charles, R.H. The Apocrypha and Pseudepigrapha of the Old Testament
Oxford: The Clarendon Press. 1913. Book of Enoch, Chapter 74, Verse 12.
(17) Pratt, John P. Enoch Calendar Testifies of Christ, Part II.
(18) Herodotus. The History. (5th century B.C.) Chicago & London:
The University of Chicago Press, 1987.
Translated by David Grene. p. 132., Book 2, Verse 4.
(19) Herodotus. ibid. p. 232, Book 3, Verse 47.

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Most peoples all over the world either modified or discarded their old 360-day calendars starting sometime in the eighth century B.C. ¹   Many of those calendars had been in use for the greater part of a millennium. In many places, month lengths immediately after that change were not fixed, but were based instead upon observation of the sky.
Priest-astronomers were assigned the duty of declaring when a new month began—it was usually said to have started at the first sighting of a new moon. ²   Month length at that time was simply the number of days that passed from one new lunar crescent to the next.

A 360-day calendar was used in Rome for a few years following the time Romulus added January and February to their calendar. Shortly after Romulus’ death a priest observed the sky and called out when there was a new moon and therefore a new month. For centuries afterward Romans referred to the first day of each new month as Kalends ³   or Calends from their word calare (to announce solemnly, to call out). Obviously, the word calendar was derived from this custom.
This practice of starting a month at the first sighting of a new moon was observed not only by Romans but by Celts and Germans in Europe and by Babylonians and Hebrews in the Lavant. ⁴   All of these peoples began their month when a young crescent was first seen in the sky. This is still done for the Islamic Calendar, but a new moon’s date is calculated for traditional lunar calendars that are currently used in China and India. ⁵
During the period when month lengths were not fixed, new moons were usually sighted after either 29 or 30 days. If clouds obscured vision on the thirtieth day, a new month was declared to have begun.
When month lengths were identical with lunations, only those that lasted 30 days were considered to be normal. This was probably because all months had previously been 30 days for such a long period of time.
In many nations, months that consisted of 30 days were considered to be “full;” those that lasted only 29 days were said to be “hollow.” ⁶   Months containing 30 days were also called “full” in Babylon, but those containing 29 were deemed to be “defective.”
After month lengths in the Celtic Calendar became fixed, those that had been given 30 days were termed “matos” (lucky) and those given 29 days “anmatos” (unlucky). ⁷   This notion has not died out. Even in our time, months of 30 days in the Hebrew Calendar are called “full” and those with 29 are deemed to be “deficient.” ⁸
In addition to their declaring the beginning of each month based upon a sighting of the new moon, priest-astronomers were also charged with pinpointing the start of a year. You might want to read about Sirius and the Early Egyptians for their method of determining when the new year began.
By observing the movement of Sirius, Egyptians came to grips with the fact that the year was longer than their venerable 360-day calendar. This resulted in a change to their method of approximating year length that had been in use for nearly a millennium. But it also caused them to wonder where the additional days came from. In order to account for these additional days, Egyptians created a myth about their sky-god, Nut. ⁹   It is related at Moon Myths.
Usually at a time later than the mid-eighth century B.C., many other peoples who had previously considered the year to be 360 days in length reluctantly changed to a calendar of twelve fixed 30-day months, but added “epagomenal days” to follow those months. Like the previously observed 29-day months, these additional days were considered to be very unlucky or unpropitious.
Calendars described in books of Enoch and Jubilees were 364 days in length. Cave 4 from a Dead Sea Scrolls excavation at Qumran produced eleven fragments of calendar texts which revealed that the Qumran community’s year was also 364 days. It “consisted of twelve months of thirty days each, plus four extra days added to each of the four seasons.” ¹⁰   No mention of intercalation beyond those four days appears in Jubilees or Enoch and was never found in Dead Sea Scrolls. In fact, Enoch claimed that the 364-day calendar year was perfect and should not be tampered with.
During the reign of the Babylonian king Nabonasser (traditionally dated between 747 and 734 B.C.) priest-astronomers in that country discontinued their practice of looking for the new moon in order to name the beginning of a month. Instead, they returned to a fixed-length calendar that had 12 months of 30 days each, but with five days added at the end. ¹¹
Two eastern Mediterranean peoples who did not embrace Islam were early Christians in upper Egypt, whom we now call Copts, and their neighbors to the south, the Ethiopians. Probably because they were surrounded by Islamic peoples, Coptic and Ethiopian churches never adopted the Western calendar. Instead, these two isolated pockets of Christianity continued to use the old 360-day calendar.
These two calendars are identical except for year number. Both of them observe three 365 day years followed by one 366 day year. Their years are divided into 12 months of 30 days each, and the extra five or six days are added after the twelfth month.
The Ethiopian Orthodox Church still schedules its religious observances over twelve 30-day months followed by a “little month” of either five or six days beginning on the Western calendar’s September 6. ¹²
Zoroastrians use a calendar of 365 days whose era began at 389 B.C., the year of Zoroaster’s birth. It consists of twelve 30-day months with five “Gatha days” added to the final month of the year. Each of the thirty days as well as each of the Gatha days has its own name. They are referred to by that name just as we speak of a day by its number in the month. Beginning in 1906 of the Common Era, some modern Zoroastrians adopted the practice of adding an additional day every four years. ¹³
One of Alexander the Great’s generals, Seleucus Necator, founded (early in the 4th century B.C.) an empire that stretched from Asia Minor to India. He established a new calendar that was essentially the same as one that had been used for some time in Syria. It contained twelve months of 30 days each and an extra five days at the year’s end. Every fourth year an additional day for a total of six days were added at the end of the year. ¹⁴
In Persia under the Sassanids, and in Armenia and Cappadocia the official system of time-reckoning was twelve months of 30 days followed by five more days at the end of the year. The Sassanian year of twelve 30-day months (plus 5 days) was kept adjusted to the seasons by observing an extra month every 120 years. ¹⁵
The 360-day calendar in Persia has been referred to as the “Old-Avestan” but the name was changed to “Young-Avestan” after five Gatha days were added at the end of each year. This happened between 510 and 487 B.C. depending on which historian is correct. ¹⁶
Mayan people in Central America also had a 360-day calendar-year tradition. Within it were eighteen 20-day periods. By the 4th century B.C., five days had been added to the end of those calendar years, but were not included as part of the original final period. Those five days were considered to be unlucky.
Mayans also developed another calendar around 500 BCE to be used for religious purposes. With it they were able to take a different approach than either Europeans or Asians. They merely reduced the number of 20-day periods in the old calendar from eighteen to thirteen per cycle, which resulted in 260-day calendar years. ¹⁷
Worldwide calendar changes described on this page occurred during a period of religious and other global social changes known as the “Axial Age.” ¹⁸

REFERENCES:
(1) Parise, Frank, Editor. The Book of Calendars.
New York: Facts On File, Inc. p. 126.
(2) Encyclopaedia Britannica Babylonian Calendars
(3) Blackburn, B & Holford-Strevens, L.
The Oxford Companion to the Year:
An Exploration of Calendar Customs and Time-Reckoning
Oxford: Oxford University Press, 1999. p. 672.
(4) Bickerman, Elias Joseph. Chronology of the Ancient World.
Ithica, N.Y.: Cornell University Press, 1968. p. 17.
(5) Doggett, L.E. Calendars.
P. Kenneth Seidelmann, Editor.
Sausalito, California   94965: University Science Books.
(6) Blackburn, B & Holford-Strevens, L. op. cit., p. 880-881.
(7) Celtic Religion
30-day months were thought of as “good” and
29-day months “bad” in the Coligny Calendar.
(8) Doggett, L.E. op. cit.
(9) Goudsmit, Samuel A. Time.
New York: Time Incorporated. 1966. p. 69.
(10) Vermes, Geza. The Complete Dead Sea Scrolls in English.
New York: Penguin. 1997 p. 335.
(11) Parise op. cit.
(12) Ethiopian Calendar (See Ethiopian calendar year at this site)
(13) Vispi Homi Bulsara. Zoroastrian Calendar
(14) Parise op. cit., p. 44.
(15) Christensen, A.  L’Iran des Sassanides. 1944. p. 168.
(16) Taqizadeh, S.H. Old Iranian Calendars
(17) The Mayan Calendar
(18) Koeller, David W. The “Axial Age”

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There are dozens of different calendars in use throughout the world. Most of them can be assigned to one of three basic types, each of which is based upon apparent motion of the moon and/or sun. Those that are based only on the moon’s phases are termed “lunar” after Luna, the Roman moon goddess. The Muslim Calendar  is strictly lunar.

Calendars whose year length is based upon the sun’s motion are termed “solar” after the Roman sun-god Sol. As the name suggests, calendars that model apparent motions of both the moon and sun are termed “lunisolar.”
Because the time that passes between new or full moons averages just over 29.53 days, it is obvious that there is a good match between natural and calendar months if the latter alternate between 29 and 30 days in length. This is the case for most modern lunar and lunisolar calendars. If based on the sighting of a new moon, two or three months of either 29 or 30 days might occur in a row.

Twelve sequential lunar phases total just over 354.367 days, almost eleven short of a tropical year. That’s why extra months are usually added to lunisolar calendars on a scheduled basis. An example is the Hebrew Calendar. One unfortunate result is that those calendars in some years are thirteen months in length rather than twelve. An unusual superstition grew out of this practice as used in the Chinese Calendar.
Oddly enough, Babylonians and other ancient peoples of Western Asia inserted extra months irregularly, sometimes two or three times a year early in the first millennium B.C.—Near and Middle Eastern people continued irregular intercalation until at least the sixth century B.C. ( Bickerman, Elias Joseph. Chronology of the Ancient World. Ithica, N.Y.: Cornell University Press, 1968. pp. 22-23. )

Babylonians eventually worked out a 19-year cycle in which there were twelve years with twelve months each and seven years with thirteen months each. The thirteenth month was inserted in a fixed pattern that kept cycles of the moon and sun even. Similar calendars were then adopted in many places near Babylon.
Between the 8th and 4th centuries B.C., permanent alterations were made to almost all calendars, regardless of their structure. See 8th to 4th Century B.C. Calendar Changes for details.

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