Ancient Hebrew Calendar

In the following series of posts, I hope to describe an old Hebrew luni-solar calendar which, if understood properly, adds considerable light to our understanding of the scriptures.

The modern Jewish calendar, as we now know it, is not the same as the one described in ancient Hebrew literature. It went through an evolutionary change from about the Persian - Greek period, probably to comply with the governing empires of that time. Commentators are aware of these changes and influences, but are hazy concerning the details of that from which it came. Leap years, for example, are not explicitly mentioned in the Bible, so it is assumed they were inserted in much the same way as a second Adar is now, albeit by primitive observation of seasons.

Modern Jewish timekeepers no longer physically observe moons, but use a formula-based method instead, to intercalate months. It was settled by Hillel in the fourth century (AD 359), and it was, for all intents and purposes, the same as that devised by the Greek astronomer, Meton of Athens, (432 BC) whose name is synonymous with luni-solar calendars. It would be fair to say that all luni-solar calendars currently being used are 'Metonic' including the Chinese, although the latter may wish to argue that theirs is older.

Meton discovered his cycle in 432 BC when he noticed that 235 synodic months almost exactly equals 19 solar years. Therefore, a thirteenth month is added to the lunar year on the 3rd, 6th, 8th, 11th, 14th and 17th years, of a 19-year cycle. In so doing, the lunar cycle is synchronised with the solar. It is an effective system, and it is not my purpose to criticise it. However, there is evidence to show that, in addition to the actual sighting of new moons, the original Hebrew calendar used advanced astronomical formulae too.

The following reconstruction describes an old luni-solar system which synchronised the heavenly bodies regularly per seven years, and again in the forty-ninth year. Following that, another forty-nine year cycle would repeat using the same formula. It may well be that the pre-metonic Hebrew calendar was even more excellent than the one which developed after.

Sabbatical Time Measurement

I'd now like to highlight a unique aspect - the shabuwa (sevens)

Earliest biblical calendar references go back to the book of Genesis, but as far as an exclusive Hebrew system is concerned, the first mention is found with instructions given to Moses at the time of the Exodus. This was the calendar that was employed during the Judges and Kingdom periods of Israel. It begins here:

“This month shall be for you the beginning of months. It shall be the first month of the year for you.” (Exodus 12:2)

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It was the month of Abib (later renamed Nisan) and what is being said here is clear; the first of Abib was to become New Year’s Day. It begs the question: If Moses was given a new start to the year, when was New Year under the calendar from which they had come? The Egyptians called it the “opening of the year” and it started with the star, ‘Sirius’, which appeared in the sky in July when the first season was ushered in by the flooding of the river Nile. They associated the life-giving inundation of their crops with Sirius, bringer of new life. In mentioning this I do not mean to discuss the Egyptian Sothic cycle. I only wish to make the point that the Hebrew calendar was not copied from Egypt. The Bible’s calendar was unique in its operation and different from neighboring countries.

The next thing to be noticed is how units of time were distinguished by Sabbath time measurement. The week was seven days, and the years were grouped into heptads. By contrast, the Egyptian 30-day month was divided into three ‘decans’ of ten days each, but the Hebrew calendar was strictly sabbatical. The following is a breakdown of time measurement in it:

• a ‘week’ of days (7 days)
• a ‘moon’ (one month)
• a ‘time’ (one year)
• a ‘time, times and half a time’ (3[super]1[/super]/[sub]2[/sub] yrs)
• a ‘week’ of years (7 years)
• a ‘jubilee sabbath’ (49 years)
• a ’70-week jubilee’ (490 years)

The ‘week of years’ was akin to our ‘decade’, and ‘jubilee’ might be likened to our ‘century’, albeit shorter. The longer ’70-week jubilee’ is alluded to in both Testaments (Daniel 9:24, Matthew 18:22) and is also mentioned in fragments of manuscripts found among the Dead Sea Scrolls. (Scroll 11Q13)

A ‘moon’ (lunar month) is typically 29 or 30 days, so when the year was completed it only reached 354 days, about eleven days short of the Sun’s 365¼ day rotation. As a result, the year slipped back each season, and an extra (thirteenth) month had to be inserted every so often. It was added at the end of Adar, according to a sabbatical formula if my proposition is correct – not according to primitive observation of seasons as it is usually assumed to have been done.



As mentioned before, confusion arises from an assumption that the modern Hebrew calendar is the same as the ancient one. It isn’t. The misunderstanding is not helped by rabbinic experts either, who make the same claims as everyone else. It’s a good calendar, it’s luni-solar, and it works. Why look for another? Also, a false credibility bolsters the assumption since the modern Hebrew calendar is not really modern. It is similar to, and can be traced back to the Greek, Persian, and Babylonian empires. Now, that is old.

But it is not as old as the one of which we speak; it goes all the way back to Moses. In my next post, I hope to look at some strange and interesting references to a ‘lost’ calendar.

Strange References to a Lost Calendar

The Old Testament makes several unusual calculations that indicate calendar formula. The first is New Year’s Day, as mentioned in the previous post. The next reference is not as obvious because its function related to religious festivals and the release of debts. I am referring to the ‘Jubilee.’

“Count off seven sabbaths of years – seven times seven years – so that the seven sabbaths of years amount to a period of forty-nine years. Then have the trumpet sounded everywhere on the tenth day of the seventh month; on the Day of Atonement sound the trumpet throughout your land. Consecrate the fiftieth year and proclaim liberty throughout the land to all its inhabitants. It shall be a jubilee for you … The fiftieth year shall be a jubilee for you.” (Leviticus 25:8-11)

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However, Jubilee is more than what meets the eye. Apart from radical agriculture and ‘debt release’ provisions, it contained precisely 600 lunar cycles from the 1st of Abib to the 7th month of the forty-ninth year! Apparently Jubilee was part of a luni-solar system designed for the keeping of time.

Then there is the Sabbath system itself. There are various descriptions of the Sabbatical years and although they don’t directly mention calendar matters, when looking beneath the surface of the text they contain formulae relating to the placement of intercalary months. We shall look at these soon.

We notice special calendar terms and numbers which occur in the prophetic writings. An example of how a year was called a ‘time’ is found in King Nebuchadnezzar’s bout of insanity. He was “driven away from human society until seven ‘times’ passed over him.” (Daniel 4:16-32) Similarly, there are mentions of a ‘time, times and half a time.’ It is 3½ years, and is one half of a Sabbatical cycle. Then, there are the curious numbers of 1260, 1290 and 1335 days which appear in the books of Daniel and Revelation. They have baffled students with commentaries calling them ‘unknown calculations’ and popular end-time writers dreaming up fanciful ideas as to what they might mean. Please deduct 30 (one month) off 1290. Please deduct 30 + 30 + 15 (2½ months) off 1335. In both cases it equals 1260 days.

If we select the Day of Atonement, the 10th Tishri (Ethanim) and add 1260 or 1290 days, it always resets itself to the Hebrew New Year Day, the 1st of Abib, three and a half years later. Our observation suggests that these unusual figures might be intercalations to an underlying calendar.

To demonstrate this, let us take the 10th day of Tishri from a known historical date in the Babylonian captivity period. Such a year was Judah’s first year in captivity, 3175 AM. It equates to our western date, 27th September, 587 BC, and has an astronomical value of 1,507,291. Three and a half years afterwards, 3178 AM, the 1st of Nisan (Abib) equals our western date, 10th March, 583 BC, with an astronomical value of 1,508,551. By deducting the astronomical values we do indeed find a difference of 1260 days! The reason why this figure (and 1290) keeps repeating as described, is because it is mathematically linked to the phases of the moon. The math is as follows:


The Bible is not the only place that references a unique ancient calendar. My next post continues looking into it, and adds more from extra-biblical sources.

Thanks for your interest Riberra.

When I first started looking into these matters about 15 years ago, I realised that the scriptures contained a ‘hidden’ calendar. Naturally, I searched other people’s writings (Dead Sea Scrolls, Jubilees, Anderson, Velikovski etc.) on the various theories.

However, they could not be demonstrated over long spans of time. Undoubtedly, the Qumran people knew something was lost, and they knew it had to be sabbatical. I mention this because people in those days were trying to find the original system, just as you and I are now. It was there to be found and they tried, but (in my opinion) never got it quite right. So, no, I dont think we should treat Jubilees or Enoch as 'canonical' - only as useful para biblical sources.

In answer to your "actual year" question, I believe we can reconstruct detailed original dates from the Exodus forward. (with limited detail back to Abraham) You will need to get my book, 'The Atonement Clock' if you want to count the Sabbatical cycles from Moses to Christ.

If you like, Ill try to give a bit more detail here than I did in the Cosmoquest forum.

Best regards,

Dead Sea Scrolls Reveal Hidden Calendar

My calendar reconstruction is based on a relatively small number of biblical texts, but that does not mean to say that extra-biblical evidence does not exist as well.

The Babylonian Talmud explains how the legal system during the period of the Judges of Israel kept track of events in terms of Sabbatical and Jubilee cycles. (Tractate b. Sanhedrin 40 a,b) The court would make a formal record of contracts, crimes etc. by writing down the 'Septennnate' (week of years) when the event took place, then by determining the Jubilee cycle in which the Septennnate belonged. For example, "The accused committed the crime on the 1st day, of the 2nd month, of the 3rd year, of the 4th Septennate, of the 5th Jubilee." This information should dispel any doubt as to whether Sabbath years and/or Jubilees were ever practiced or not, at least for the Judges era. It also expresses calendrical terminology.

Such calendar language as described above is also used in the ancient 'Book of Jubilees', copies of which were found among the Dead Sea scrolls. For example, it relates Jacob's move to Egypt as follows: "And Israel went into the country of Egypt, into the land of Goshen, on the new moon of the 4th month, in the 2nd year of the 3rd week (of years), of the 45th Jubilee." (Jubilees 45:1) For whatever else we might think about parabiblical literature, one thing is sure; Jewish readers as early as the second century BC were aware of a former Sabbatic method of dating.

When studying the inter-testament era, it becomes apparent that Babylonian, Persian and Greek elements had been added to the original calendar. The all-important month of Abib reappears after the captivity as ‘Nisan,’ a Babylonian name. (Nisanu) Sometime after that, Jubilee observances ceased, then New Year was shifted from Abib to Tishri. We don’t know exactly when these changes took place. I suspect Jubilee stopped soon after Nehemiah. Hecataeus of Abdera, a Greek historian who lived during the conquests of Alexander, is credited with saying, “Under the rule of nations during latter times, namely, Persians and Macedonians ... the Jews greatly modified the traditions of their fathers”. (Diodorus Siculus 40:31)

Alfred Edersheim adds, “after their return from exile, the Jews dated their years according to the Selucidic era.” (The Temple, ch. 10, page 204) It is known that the Seleucid New Year was Dios which was the Greek equivalent to Tishri, so it would be fair to surmise that the New Year change came about then.

Also, the Dead Sea Scrolls reveal a serious debate concerning changes to the inter-testament period calendar. "All the children of Israel will forget and will not find the path of the years, and will forget the new moons, and seasons, and Sabbaths, and they will wrongly determine all the order of the years. For this reason the years will come upon them when they disturb the order ... they will go wrong as to the months and Sabbaths and feasts and Jubilees.” (Jubilees 6:33-37) Thus the Essenes of Qumran rejected the post-Babylonian calendar and the temple authority’s festival dates, because they believed the true calendar had been abandoned by the priests and replaced with an alternative system. Their scrolls show instead a 364-day solar year that was divisible by seven. This, they believed to be the original system founded by Enoch, and those who departed from it were "apostate."

Attempts to apply leap-year formulae to the Enochian year have not been satisfactory, but the fact that the Essenes attempted to recover a 'lost' Sabbatical calendar speaks loudly that there was one to be found! The following reconstruction does indeed find such a pre-Metonic calendar, and I would now like to put forward for consideration the precise intercalation formula and astronomical details of the original Hebrew calendar.

btw, anyone is welcome to reply.

keras said:

As the earth is about to be shaken from its place, Isaiah 13:13, and our orbit speeded up to a 360 day year, all this discussion is purely academic.
The proof of a soon to happen 360 day year is in the time periods given in Daniel 12 and Revelation. The 1260 days, 42 months and 3.5 years, will all be perfectly equal.

You mention Velkovsky. His books detail the terrible event that changed the earths orbit at the time of the Exodus, from the original 360 day year, to 365.24. A difficult fraction, that has taken centuries to reconcile, the Jews especially have totally messed it up. Their dates for the Appointed Mo'ed's cannot be relied upon.

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Thanks for mentioning the 1260 days. The Bible also mentions 1290 days. Keep a look out and Ill put up a diagram on these figures. I wish Velkovsky was still alive so we could chew the rag about it.

Riberra said:

Thanks !
-First that should be interesting to know from what basis the actual Hebrew calendar arrive with 5,777 years ?

-Second to try to see if that number 5,777 match [or not] with the ancient Hebrew calendar that you describe ?

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5777 years ago was when the world was created, according to the modern Jewish calendar. Bear in mind, Jewish chronology was fudged during the Persian period. They do not say why, but Christian historians believe it was a deliberate attempt to obscure Daniels 70-week countdown to Jesus of Nazareth.

Dont get me wrong; The Jewish luni-solar calendar is a good one. But it is not the original one. Also, their count back to Genesis is not so good.

Division of the Week

Every luni-solar system, be it Hebrew, Greek or Babylonian, realises that the lunar year needs adjustment about every third year. Therefore it is not by coincidence that the Hebrew heptad of years was divided in half and called, a 'time, times and half a time.' This term is mentioned in the Bible often enough, but usually in a 'prophetic' setting. That aspect has been abused by end-time 'crazies' and 'date setters', so I'll limit our discussion of the division of the week to its function in the calendar.

The division occurred; it seems, on Israel's all-important festival, the Day of Atonement. The D.of A. was the 10th of the seventh month, but it should not be supposed an arbitrary date of religious significance only. When we count 3½ years from the beginning of a Sabbatical cycle, it comes to a total of 1278 days to the start of the D.of A. in the middle year. Now, this is interesting, because the number of days in 3½ solar years is the same; so the 10th of Tishri must have been a marker showing where the lunar calendar intersects with the solar.

That is not all. When we count from the end of the Day of Atonement 1260 days, it resets itself, as mentioned before, to the start of the next Sabbatical cycle. So, the special festival in the middle year is actually a 'fulcrum' between two significant counts. Each 'time, times and half a time' had an additional month added to the 'base' 42 months, making 43 lunar months on both sides - a total of 86 lunar months altogether. Please examine the diagram taking note that the Day of Atonement stands independently between the two counts.




Old Testament scripture alludes to the division of the week by Daniel's term, 'midst of the week' although, in this case, it referred loosely to the sacred festival period of the middle year. It also mentions an extra leap month, expanding the 1260 days to 1290 days. By understanding how the number of days count to New Year’s Day, we are provided with part of the answer to what the prophet meant when he said: "From the time that the regular burnt offering is taken away and the abomination that makes desolate is set up, there shall be 1,290 days." (Daniel 12:11) 1290 days to what? The sentence doesn't seem to lead anywhere, and yet the answer is what the reader is looking for! However, Daniel would have expected his original readers to have known that he meant from the Day of Atonement to New Year's Day.

Indeed, when we follow the moon over extended periods, we find the ancient Sabbatical cycle alternating between 86 and 87 months until seven 'weeks of years' completed the Jubilee of forty-nine years. In the case of the alternate 87 months, the equation would show a 'time, times and half a time' of 1278 days on one side, and 1290 days on the other. In other words, a total of three months were added in those cases.

I have checked this model over hundreds of years, and come to the conclusion that by combining the formula with actual sightings of New Moon, the calendar would have been virtually mistake-proof. For a recent example, let us take the 1st of Nisan, 2000 AD and add 1278 days. It comes to the 10th of Tishri 2003 AD. If we count this hypothetical 'day of Atonement' then add another 1260 days, it returns to the 1st of Nisan, 2007 AD. The system is no longer in use of course, but it works just as well today as it did in biblical times! (I'll provide a link to actual dates later)