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Calendar Systems Part 2 - Calendars during Bible Times

In part 1 of this article, we examined the types and components of calendars.  In part 2, we explore the political and historical environments of the major nations in which the calendar systems developed during Bible times and the Early Church period.

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Political and Calendar Systems during Biblical Times

In this chapter, we are primarily interested in the political and calendar systems that have played an important role in helping us to date the various characters and events of the bible.  We begin with those of God’s chosen people.

Israel (Jewish Calendar)

It was commonly believed that the earliest Jews used a lunar calendar, but in doing research for his The Annals of the World, James Ussher (1581-1656), noted historian and Archbishop of Ireland, discovered that they used a lunisolar system instead.  According to Ussher, the early Jewish calendar consisted of twelve months of thirty days with five added days, or six added days every fourth year (leap year).  A day would then be dropped as required as the seasons began to drift after so many years.  This system appears to be in use from the Egyptian captivity (beginning in the nineteenth century BC) until the Judean exile (early sixth century BC).  Biblically, the Nation of Israel is considered to have begun as a theocracy in the mid-fifteenth century BC with the giving of the law to Moses at Sinai shortly after the Exodus from Egypt.

According to the Jewish Talmud, the Jews adopted the names of the Babylonian months during the exile in Babylon (late sixth century to mid fifth century BC).  This is consistent with Scripture, since we see the Babylonian month names appearing in the post-exilic books of Ezra, Nehemiah and Esther.  One oddity exclusive to the Jewish calendar is that the New Year (Rosh Hashanah – “Head of the Year”) begins with the seventh month of Tishrei (Lev 23:23-25), the anniversary of the creation of Adam and Eve in Hebrew tradition.  The first month (Nisan) is reserved for Passover (Ex 12:2).

In addition, the switch was made to a six 29-day months, and six 30-day months calendar, for a total of 354 days per year, and an extra month was added as needed to synchronize with the Biblical feasts and festivals.  This leap month was placed at the end of the last month (Adar), and was simply called Adar Sheni (Second Adar).  Beginning in the fourth century AD, Hillel II began adding the intercalate month to seven out of every nineteen years based on previous Babylonian and Persian calculations.

In the modern Jewish calendar, the year is dated from the traditional Jewish date of Creation, Nisan 1, 3761 BCE.  At the time of this writing (early June 2013 AD), we are in Sivan 5773 on the Jewish calendar.  The year conversion can be calculated by adding 3760 (before Rosh Hashanah) or 3761 (after Rosh Hashanah) to the modern Gregorian year (AD).  Note also that the Hebrew calendar is missing approximately 240 years from around the time of Alexander the Great, so we are actually about 6013 years from creation according to the tradition.  This would also place creation about 4001 BCE, which is very close to Ussher’s calcs of 4004 BC.

Bible authors tied many events to Jewish calendar months, but none to its years.  This is probably because the Jews didn't establish a consecutive annual numbering system until later.  Since years were typically numbered from the reign of a king or from an important event during Biblical times, the point of origin would often reset.  Fortunately, many bible characters and events are mentioned and dated in political and historical documents of the surrounding nations, particularly Egypt, Babylon, Assyria, and Persia during OT times.  We also have Persian, Greek, and Roman documents to help date some intertestamental and NT characters and events.


The Egyptians were probably the first people to develop a solar calendar, dating back to the third or possibly even the fourth millennium BC.  Like most subsequent solar calendars, it came about out of necessity.  In fact, it wouldn’t be much of a stretch to say that the very existence of the Egyptians depended on it.

Rainfall was extremely rare in ancient Egypt so the Nile River was essential for the nation’s survival.  Since the Nile furnished the Egyptians with water and transportation for trade, the majority of the population lived near the river.  The combination of melting snow and heavy summer rains in the Ethiopian mountains resulted in the Nile flooding the flat desert land each year.  After the floods, fertile black mud was left in place of the otherwise uncultivable red sand land.  Since crops could only grow in the areas that flooded, it was crucial to be able to predict the dates of the floods (from June to September on our modern calendar).  Since the late 1960s, the annual flood is controlled by the newly constructed Aswan Dam, but in ancient times the calendar was their only almanac.

Because the earlier lunar based calendar failed to accurately predict the annual flooding of the Nile River, the Egyptians put together a 365-day solar calendar (with leap day as required) based upon the rising of Sirius, aka the “Dog Star” from the Canis Major (Latin for “greater dog”) constellation.  Due to its close proximity to our solar system, Sirius is the brightest star in the night sky, and the Egyptians observed that it was visible just before sunrise a few days prior to the flood each year.

Even after the adoption of their solar calendar, the Egyptians maintained their lunar calendar for certain religious activities and later added a lunisolar civil calendar for government affairs.  They also augmented the custom of dating events by a certain year of a leader’s reign that likely influenced the practice found in our Hebrew Bible.  These lists, left by the Egyptians, Assyrians and Babylonians of consecutive rulers and the length of their reigns, are indispensible in our efforts to date various Bible events.


The Babylonians appear to have come into prominence around the nineteenth century BC, about the time the Israelites (all 70 of them) moved to Egypt under Jacob and Joseph.  They employed a 12-month calendar of alternating 29 and 30-day months, with addition of an extra month in three out of every eight years.

The Babylonian empire reached her zenith of power throughout the Middle East in the late seventh and early sixth centuries BC under King Nebuchadnezzar II, who conquered Judah and exiled many of the Jews to Babylon for 70 years.  Babylon was conquered by King Cyrus of Persia in 539 BC, and the Israelites returned home in three stages, 538, 458 and 445 BC.


After conquering Babylon, the Persians adopted the Babylonian calendar as the standard throughout their empire, which stretched from what is now modern day Iran into northern Africa.  Babylonia dates have been found in a few Aramaic documents dating from the time of the Persian occupation in Egypt.

Early in the fourth century BC, new calculations based on enhanced knowledge of astronomy resulted in an extremely accurate upgrade to Babylonian lunisolar calendar.  The alternating 29 and 30-day months (12 total per year) was retained, but intercalating months were now added in 7 years in every 19-year cycle (in years 3, 6, 8, 11, 14, 17 and 19).  This system, which greatly influenced Hillel’s Hebrew calendar, produced a calendar with an error of less than 15 minutes per year.


Assyria was subject to Babylon for much of her early existence before gaining independence in the latter half of the second millennium BC.  Her influence fluctuated for centuries before entering a period of dominance in the early eighth century.  The Assyrian Empire extended through much of the Middle East and into Egypt.  Assyria conquered and exiled the northern tribes of Israel (Samaria) in 722 BC before falling to an alliance between the Babylonians and the Medes.

Regarding her calendar, the Assyrians never really broke free from Babylonian influence.  Even at the height of her power, Assyria continued to utilize the Babylonian calendar.

Greek Empire

The Greeks, under Alexander the Great in the fourth century BC, came as close to conquering the known world as any empire before or after.  Indeed, portions of their Greek culture continue to influence us even today.  Their calendar however, is not one of them, probably because nearly all of the Greek city-states utilized their own.

Most were based on the early Babylonian lunisolar calendar with the alternating 29 and 30 days months and a leap month in three of every eight years, but their similarity went no further.  Most had differing start times for the year and names for the months.  For the most part, they synchronized tolerably with the seasons, but don’t appear to have been updated as new astronomical data became available.  Thus, the Greek calendars failed to gain a foothold, and Greece fell under Roman control in 147 BC in the Third Punic War.

Roman Empire

The founding of the Rome (traditionally dated 753 BC) is steeped in myths and legends.  Some details may vary slightly, but according to the Roman mythology, the city was founded by Romulus and Remus, twin sons of the Roman war god Mars and a virgin princess (ala Mary).  Since the sons were in line for the throne of an ancient Italian city, the current ruler executed the mother and cast the twins into a basket on the Tiber River (ala Moses) where they were rescued and raised by a she-wolf.  When grown, they killed the ruler, placed their grandfather on the throne, and decided to build a town of their own.  They chose an area on the banks of the Tiber near the location where they were rescued by the wolf, but couldn’t agree upon which hill to build.  This dispute led to Romulus killing Remus and becoming the first king of Rome.  He settled the new city with outlaws and runaway slaves, and kidnapped women from a neighboring tribe (which he eventually subjugated) as wives for the men to populate his city.  Legend also has it that Romulus never died, but was carried to heaven in a fiery chariot (ala Elijah) by his father Mars.

By comparison, the actual account of Rome’s founding is rather boring.  The city actually developed from a group of independent settlements on and around seven hills near the Tiber River.  The various settlements decided to band together for protection against enemy attacks, but there were some immediate obstacles.  Some of the settlements were located on opposite sides of the river, and most of the hills were surrounded by marshland.  Fortunately, the river was relatively narrow at this location, but the building of bridges and draining of swampland still took many years.  The old saying “Rome wasn’t built in a day” was originally coined in France in the twelfth century AD.  Even though the allegorical expression wasn’t used to describe the actually historical account, it would certainly be historically correct.

In the classic western “The Man Who Shot Liberty Valance”, Ransom Stoddard's (Jimmy Stewart) very successful political career is launched on the mistaken belief that he shot the famous outlaw in a gunfight.  He finds out the Valance was actually shot from the shadows by Tom Doniphon (John Wayne) who swears Stoddard to secrecy.  After Doniphon's death near the end of the movie, Stoddard reveals the real story to newsman Maxwell Scott.  Scott thanks him and begins to board the stagecoach as Stoddard asks, “You're not going to use the story, Mr. Scott?”  Scott then utters the classic quote, “No, sir. This is the West, sir. When the legend becomes fact, print the legend.”  Of course, those with a Christian worldview realize that false legends don't actually become facts, they are only accepted as facts (a truth that is often lost to secularists), but we could certainly apply this quote to early Rome as well as the American west.  It is sometimes difficult to determine the exact point where the legend ends and reality begins.

With that in mind, the first Roman calendar is usually attributed to Romulus himself.  This lunisolar calendar consisted of 304 days divided into 10 months covering the agricultural season (winter months were not counted.  It is thought that Romulus’ successor, Numa Pompilius divided the year into twelve lunar months totaling 355 days circa 700 BC.  Any intercalating to synchronize the calendar with the solar year was done haphazardly or not at all (superstition prevented adding days to some years, particularly during time of war).  At times, the calendars were also manipulated for political purposes.  The priests who were in charge of the calendar occasionally shortened or lengthened the years depending on which politicians were in office; even receiving bribes periodically.

By the second century BC, the calendar was several months off.  It is not unusual to find the same astronomical event dated months later on calendars from neighboring states.  This would change with the reign of Gaius Julius Caesar.

Julius Caesar was elected pontifex maximus (chief priest) in 63BC, but was initially engaged in military conflicts, including siding with Cleopatra in the Egyptian Civil War.  Upon returning to Rome in 46 BC, he was proclaimed dictator by the Senate.  On the Ides of March in 44 BC, he was assassinated by a group that included his son Brutus.  Julius’ death effectively ended the Roman Republic and paved the way for the Roman Empire.  The lower and middle classes, with whom Julius was extremely popular, purged his assassins from the land.  In the void, Octavian defeated an alliance of Mark Anthony and Cleopatra to become the first Roman Emperor in 27 BC, taking the name Caesar Augustus.

Yet, while in office, Julius Caesar consulted with the Egyptian astronomer Sosigenes and instituted the Julian calendar that remained in common use for the next sixteen centuries, and is still in use by some eastern orthodox churches.  The calendar’s 365 days were divided into twelve months with similar names and the same lengths as those we are acquainted with today.  Likewise, every year that was divisible by four was also a leap year, adding the day to February.

The Julian calendar went into effect on January 1, 45 BC, after adding 90 days to restore the missing days introduced by the previous calendar.  At this time, it was the most accurate calendar to date.  Yet, it’s year was just over eleven minutes too long, giving an error of approximately one day every 128 years.

During the first thousand years of its existence, there were two dominate dating systems applied to the Julian calendar.  The first was based on the regnal year of the current or significant former emperor.  Some of the most oft-used were Diocletian, Constantine, and Augustus, as well as Justinian from the sixth century Byzantine Empire.  In the other dating system, the years are designated by the suffix “AUC”, an abbreviation of the Latin phrase “ab urbe condita” meaning "from the founding of the City”.  The “city” is of course Rome and as we previously mentioned, its traditional founding is dated as 753BC (or 1 AUC).

There is some debate as to which system was most popular during the first millennium.  The majority of the evidence appears to favor the regnal dating system, which has been found in the writings of many German and eastern European historians and authors.  The AUC system appears to have gained popularity after the middle ages, particularly with the re-publishing of much classic literature during the Renaissance era, but the AUC designations are thought by some historians to be redactions.

In the latter half of the first millennium, a third dating system was introduced and applied to the Julian calendar.  It was none other than our modern BC-AC system.  We now examine its inception and significance in Part 3 – Our Origin of the Anno Domini Dating System.

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