Bible and calendars
Bible and calendars




As far back as the 3rd millenium, the Egyptians knew the 365 days year. The alternation of 30 and 29 days months, enabling them to catch up with the successive lunations, must have looked like early evidence.

In these conditions, 12 lunar months make 354 days, thus leaving a 11 days deficit when compared to the solar year.

The fraction 11/29,5 or 11/30 is quite intuitive to define the necessary complement of lunation to match the seasonal year.

The Chaldeans, who were unremitting observers of the heavens, did indeed notice that the heliacal rising of Sirius - that is its first appearance in the sky at dawn - shifted forward a day each 4 years, which corresponded with half a month per lifetime. This could not escape the attention of these clever astonomers, according to whom the year is 365,25 days long.

As for lunations, which length can vary up to 14 hours, quite a long series of them - as well as eclipses - had to be observed before obtaining an acute average value of their duration.

In consideration of which the acurate observer will have undoubtedly noticed that 49 lunations equal 1447 days and 62 lunations equal approximately 1831 days. That gives us an average length of 29,531 days per period and 12 lunations are 354,37 days long. Hence the fraction of month needed to complete the year is 10,88/29,531 = 0,368.


Keeping in mind that the Chaldeans used the sexasegimal number system (60 basis), the nearer fractions are 22/60 = 0,3666 or 23/60 = 0, 3833.

We see here that their first intuition turns out to be a very good approximation, since the Chaldean year comprises 12 + 11/30 lunations , or else 30 Chaldean years comprise nearly 371 lunations (within 1,5 days).

This constitutes the basis of a 30 years lunisolar calendar, made of 19 years with 12 lunations3 and 11 years with 13 lunations, that is a total of 10 956 days -> average year of 365,20 days.

When was this discovery made ?

I shall refer here to an article by Francis Joannès about "The Almanacs of Babylonian Astronomers" in Dossiers d'Archéologie n° 191, p. 48-55, dated March 1994, in which he says :

" During the second half of the 1st millenium BC, the Babylonians observers had apparently understood that there were celestial mechanics.
[...] As soon as the Babylonian VIIth century BC a systematical observation of the state of heavens was set up.
[...] The scientific development of Babylonian anstronomy began much sooner than the Seleucid era.
[...] The introduction of a 19 years cycle in the calendar certainly dates back as far as after Alexander the Great came to Babylonia (-333)."

We can thus, in all likehood, conclude that the Babylonians had, as soon as the VIIth or VIth century BC, worked out their own 30 years calendar cycle, distinct from that of the Greek Metonic cycle. Another clue tends to confirm this ; here is the list of the Akkadian calendar months (2nd millenium BC) :

Ulûlu shamu

Adaru arkû

We cannot but notice that there are 2 spots of reduplication of a month during the 13 lunations years, whereas there is but one in the Hebrew calendar that follows the 19 years Metonic cycle4.


Have any other peoples reached such a high level of knowledge ? It is very likely, as long as they had long practiced observing the stars. In fact, Diodorus Siculus, a Greek historian from the 1st century BC, does mention the Hyperboreans, "farther than the northern winds", which worship the sun in "a spherical temple" and very closely examine the moon since it seems so close to earth in that place.

It is impossible not to think about the Celtic people and their megalithic monuments, and particularly about Stonehenge in South-Western England, which consists of a series of circles, some of them made of regularly spaced holes - now filled in but still visible - and others of erected stones, the higher of which stand towards the centre.

This long known megalithic monument has been widely talked about since the publication of the astronomer G.S. HAWKINS' Stonehenge decoded5 in 1965, in which he suggests that it must have been, during the years 2000 to 1600 BC, an eclipse foreteller.

It is very surprising indeed that people were able to foretell the precise moment of an eclipse but were not able to work out a proper calendar.

The monument itself comprises, inside a circular ditch standing as an enclosure, two types of rocks, perhaps brought here at different times but were very carefully put and set up.

- About 80 blue rocks of averagely 4 tons, most of which have been moved or have fallen down. - Sandstone rocks, also called "sarsen", much bigger and originally placed in two very distinct groups :
- a circle of 30 stones standing up and covered with a continuous and well adjusted lintel of 30 others rocks ;
- a "horseshoe" of 5 trilitha made of 2 stones of 40 to 50 tons covered with a 23 to 26 feet high lintel.
- an eleventh rock "of sacrifice", of the very same material, shape and dimensions, lays half burried just outside the first circle of rocks. It must originally have been set up (maybe at the center of this monument).

Farther away, outside the enclosure, an uncut but pointed rock serves as a "lug" or milestone for astronomical alignments seen from the centre of the monument during the summer solstice.

This quite elaborate layout of the premises - made of 30 arches and 11 set up stones - directly refers to the 30 years calendar cycle of 11 to 13 lunations which has been mentionned above, all the more so since these 80 blue rocks are divided in two distinct groups :
- In the middle of the trilitha "horseshoe" are 19 stones which have been erected at the very beginning (8 of which are still up).

- Between the "horseshoe" and the 30 arches circle stood another circle of about 60 rocks which are difficult to count precisely ; Hawkins reckons they must have been between 56 and 616 . 62 is a meaningful number since it is the precise number of lunations encountered in Coligny's Celtic calendar and corresponds as well to one lustrum (cf p 19) linked to a 30 years cycle.

Thus we can only come to the conclusion that, since 2000 BC, from the Euphrates banks to the Atlantic shore, the lunisolar calendar of 30 years cycles came before the 19 years Metonic cycle, as far as Antiquity peoples' use is concerned. Further evidence can be found in Pliny the Elder, a Latin author of the 1st century, who mentions that the Gallic used a 30 years cycle too7 . Pieces of a bronze tablet were also found in 1897 in Coligny (Ain, France) ; set together they formed a Gallic calendar of 62 months which can be linked to the 30 years cycle.

This archeological piece is now displayed in the Gallo-Roman Museum of Fourvière in Lyon (France).

In short, this calendar cycle - that we shall call "antique" - left many archeological remains :

- set in stone in England
- on clay in Babylonia
- set in bronze in Gaul
- on parchment in Rome
before becoming more precise formalizations :
- The Metonic cycle in the Orient, which can be found underlying both the current Hebrew calendar and the traditionnal Chinese calendar.
- The Julian calendar which has ruled the romanized Occident for 1600 years before turning into the current Gregorian calendar.


This "antique" cycle which endured for more than two milleniums has then sunk into oblivion.
But the term LUSTRUM remains, both as a fossil and a testimony from bygone days... which shows on the surface in two biblical texts :
- in Daniel, 9, 25 an entity of 62 parts of time is mentionned (but poorly translated).
- in Ezechiel, 1, 1-2, a "thirtieth year" is mentionned.
But we shall discuss these texts later on.

N.B. : Let us remark that bronze, an alloy of copper and pewter, was invented in Mesopotamia. Tin being quite abundant in Cornwalls, commercial exchanges must have taken place, certainly favouring the similitude of their calendars.

3We can find another approach of the very same result, based upon a series of 13 lunations, the measures of which are written on Babylonian tablets and quoted in : Parisot J.P. and Suagher F., Calendriers et Chronologie, Paris, Masson, 1996.
4For further details, see Annexes p. 83-85 : Babylonian Chronology.
5Hawkins, G.S., Stonehenge Decoded, New-York, Dorset Press, 1987.
6Hawkins, G.S., Stonehenge Decoded, New-York, Dorset Press, 1987, p. 59.
7Pliny the Elder, Natural History, "Saeculi post tricesinum annum", XVI, 250.
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