Using Parallel Calendars

Previous articles have laid out the foundational issues for building a time line from Adam to the present. This one deals with the philosophy of how the answer should be structured.

In general the Bible’s own time system will be used in this exercise, without conversion to modern calendar dates. This allows the precision of the exercise to be matched to the Bible’s natural precision, without loss because of conversion.


My first exposure to intricate, long-distance, day-accurate, time intervals in the Bible was a presentation of someone’s belief on the structure of Daniel’s seventy weeks.[1] The presentation was a copy of that currently published in the Left Behind series. The fundamental math being over 100 years old, and produced in what I later learned was an extremely dubious motive.

I had heard this presented before, but instead of a new-believer, accept-everything attitude, I looked at the presentation as I would someone presenting similar materials at my place of employment. What I saw this time startled me.

The standard, and quite popular presentation of Daniel’s 70 weeks begins with a supposed date for decree to rebuild Jerusalem. It then ends at the time of Jesus’ crucifixion. In order to not publish something so stupid I will not reproduce the math here.

This presentation was riddled with analytical errors at several levels. The most obvious was lack of any error analysis, analysis that should have been applied to most of the steps.

All empirical work done in High School level chemistry and physics classes is done under a system called error analysis. Each measured value includes an estimate of the measurement tolerance that goes with that value. When students have numbers that come out with very high precision the instructor can usually tell that the numbers have been faked. I’ve seen several attempts at forgery in my scholastic history and high precision without highly precise instrumentation is a dead give-away that a forgery is underway. The Left Behind series’ analysis of Daniel’s 70 weeks reeks of forgery for this reason.

The world currently uses the Gregorian calendar. It supplanted the Julian calendar, in use in the Western world in a stable way since the year 5 AD. Before the year 46 BC the Roman Senate established the shape of the calendar by legislative fiat. This was similar to the way the US Congress today sets daylight savings time rules by legislative fiat.

The records of the Roman Senate do not pass down to us, and the exact calendar structure and exact dates has a error component that gets larger the farther back in time someone may care to measure. That error component is something like 10 days, plus or minus, on average for each year before 46 BC. The Left Behind series’ 490 years of Daniel has over 400 years in this troubling time and so no date from historical events at that age should be measured more tightly that about 10 years.

Any attempt to claim a more accurate date from historical events at that antiquity requires an analysis as to why the value chosen is considered accurate. No such analysis is ever offered by the classic analysis of Daniel’s 70 weeks.

Note that this error analysis problem does not apply to astronomical events that have been back-calculated using modern computers because they are not actually measured against man-made ancient calendars. Understand the source of this error is poor human record keeping.

The Other Problem: Large time measurements in ancient history

The other problem, the more profound problem, with the Left Behind version of Daniel’s 70 weeks was the use of very large day-counts across this nearly 500 year period.

People don’t usually measure time with day counts even past a single month. How could long distance time measuring be done better? Especially ancient long distance time measuring?

The answer, it turns out, is simple: Recast all of recorded time onto the Bible’s own calendar.

This answer is based in a profound idea: That the Bible started out with an accurate time keeping system, accurate enough even to record the days of Noah’s flood.

To the extent that the Bible records an accurate date, then it was day accurate on the time system used to write the Bible.

When the calendar was lost along with nearly everything else mentioned in the Bible dealing with the Exodus, the Tabernacle, Solomon’s temple and even the texts themselves, so, too was the calendar lost. That accuracy cannot be recovered by back-porting the Gregorian calendar. We must work forward that ancient, accurate, time system all the way to the modern era and then convert modern dates and events to that time keeping system.

By leaving time on the Bible’s calendar, every ancient dated event remains in its Biblical accuracy, often to individual days.

That process of converting events dated on the Julian or Gregorian calendars will carry with it the natural tolerance that all events dated on those calendars carry. Indeed, even in this modern technical world, media outlets like CNN rarely, if ever, date events accurate to the day. Why should we expect ancient off-Bible sources do to any better?

The Bible Calendar

Previous articles have dealt with the structure of the Bible’s 30 day calendar. That calendar has a 50 year, or 18,240 day periodicity, far simpler that the 400 year periodicity of the Gregorian calendar. Each day, since Adam’s first day, is simply another day on that same 30 day/month, Jubilee cycling, Bible calendar.

Nothing could be conceptually simpler.

Until the fall of Jerusalem to Nebuchadnezzar’s army, every dated event in the Bible can be accurately dated back to Adam, since it can be dated to the Bible’s internal calendar system.

That same calendar still runs today even if nobody is aware of what day it may be on that calendar. By the end of this article series the mathematical relationship between the Bible’s 30 day calendar and the modern Gregorian calendar will be shown. With that we have a mathematically error free calendar system with which to measure modern headline events.

The Steps

Getting to a working parallel Bible calendar is rather intricate. The steps are what remains in this Bible Time Theory section.

The result of this process allows validation of various date intervals, especially year based intervals, by simply checking to see that the year numbers in different Bible dates are off by the indicated number of years.

Long distance day numbering and counting is also possible, and not only can Daniel’s 70 weeks be better placed in history, it can be shown day accurate and at the same time include all the needed supporting error analysis.


The Bible Time website and related tools are built using the Bible’s own 30 day/month calendar. That calendar cycles every 50 years and began at the start of Adam’s 1st year. It continues to this day.

Instead of converting Biblical events to the modern Gregorian calendar and loosing all ability to apply the Bible’s own prophetic time system, the strategy followed here is to leave all events stated on the Bible’s calendar. This includes modern events that will eventually be shown to be datable on that same Bible calendar.

1. Daniel 9:1