The existing references make clear that the ancient Israelites - exactly as one would expect - continued to maintain an Egyptian calendar where a year was three hundred and sixty day made up of twelve months and thirty days. There is absolutely no evidence that suggests that any of the familiar Hebrew months were known to the author of the Torah. The Samaritans and Jews are divided to this day about whether the year begins in the spring or the fall. The reason for this is that they are forcing a later (Babylonian) system unto the original Egyptian system of the Torah.
Believe it or not the Samaritan sect of the so-called 'Dositheans' continued to maintain the original Egyptian calendar. They maintained a calendar of twelve months of thirty days. This connection between Dositheus and the number thirty always comes up in later references. The Pseudo-Clementine Literature have Dositheus inherit a baptismal sect that venerated the number thirty. Origen strangely infers that there were only 'thirty' Dositheans left in the world (C Celsus 6.11) but we learn that Eulogius of Alexandria was still writing against Dositheans in the city centuries later. Origen's reference is certainly cryptic.
The Dositheus were n my opinion the guardians undoubtedly of the original system which is revealed in the following reference:
Three times thou shalt keep a feast unto me in the year. Thou shalt keep the feast of unleavened bread: (thou shalt eat unleavened bread seven days, as I commanded thee, in the time appointed of the month Abib; for in it thou camest out from Egypt: and none shall appear before me empty. And the feast of harvest, the firstfruits of thy labours, which thou hast sown in the field: and the feast of ingathering, which is in the end of the year, when thou hast gathered in thy labours out of the field.[Exodus 23:15 - 16]
Abib is not another way of identifying the month of Nisan. Later commentators just invented this argument to get around the fact that the Torah was actually developed from an Egyptian calendar. As Eduard Mahler pointed out in his paper The Hodes Ha'abib in which the Exodus Took Place and its Identification with the Epiphi of the Egyptian 'Nature Year' in the Proceedings of the Society of Biblical Archaeology, November, 1905, Vot. XXVII, Part 6.
Among the Egyptians there was, besides the usual year-forms (Sothis-year and vague year), also a so-called "Natural-year" which had its beginning at the first ripening of the field-produce, and whose New Year's Day coincided with the the day which the later Israel kept as a festival (hag habikkurim). In the Zeitschrift für Aeg. Sprache 1882, 169ff, Erman publishes "Ten contracts of the time of the Middle Kingdom," and among these the second records the gifts which the hour-priests were obliged to deliver to the High Priests (ober-profeten) on New Years day. On the other hand, the latter were obliged to give a part (hqt) "from every field of the endowment property, the first-fruits of the prince's property, in the same way that every subject of Siut does with the first-fruits of his harvest. Also among the husbandmen, every one offers of his first-fruits in the temple."
On New Year's Day (which is here written with the sign X and therefore indicates a permanent year) the first-fruits had to be brought to the temple. The Egyptians then already possessed at the time of the Middle Kingdom, besides the usual year-forms, another whose New Year's Day coincided with the first ripening of the field produce. This " Nature-year " was permanent, as is self- evident; but it was not identical with the Sothis-year, which was the normal year of the Egyptians, as that began on July 20 (Julian calendar), and on that day the harvest was long past. It cannot be the vague year either, as at the time of the Middle Kingdom— ie, circa 2100-1600 BC — the 1st of Thoth of the vague year fell between September 20 and February 1, when there could be no thought of "first-fruits." The New Year's Day of the above- mentioned contracts can then only indicate a special Nature-year which began at the gathering-in of the "first-fruits."
By this, however, we obtain the knowledge of the most important cult-historical fact. On New Year's Day of this Nature-year the "first-fruits" were brought to the temple of Siut. When we remember that the months of the respective year-forms of the Egyptians bore the same names, that therefore the first month of every year-form was called "Thoth," the second bore the name "Paophi" etc., then we see that the following days preceded the New Year's Day, ie, Thoth 1st, of every year-form, and therefore also of the Nature-year : —
5 Intercalary days,
30 days, month Mesori,
30 days, month Epiphi etc.
If we then count back 50 days from the New Year's Day of the Nature-year, on which the first-fruits had to be brought into the Temple, on which the "first fruits" had to be brought into the Temple, we come to Epiphi 16. According to the Bible (Lev. xxiii, 15, 16), Israel was commanded to count 50 days from the 16th of the first month, which month was also called "Hodes ha'abib," i.e. the month Abib, in order to celebrate the "Hag-ha-bikkurim" = the Festival of the first fruits. The analogy between the usage of the ancient Egyptians and that of Israel is so striking that we can both identify, without anything further, the Hag ha-bikkurim of Israel with the New Year's festival of the Nature-year of the ancient Egyptians, and also the month of Abib in the Bible with the month of Epiphi of the Egyptians - especially the Epiphi of the Nature-year.
The hodes ha'abib in which the Exodus took place, is therefore to be identified with the month of Epiphi of the Nature year of the Egyptians.
The point of this of course is that I think that we can show that the first Christians in Alexandria weren't compromising 'the true lunar calendar' of Judaism when they adopted the 360 day year of the Egyptians. They must have seen themselves as 'restoring' the original truth by going back to the original calendar of Israel. I am also intrigued if this understanding might shed some light on Paul's use of the term 'firstfruits' which as we have seen must have been connected with Pentecost.
Oh and two more things:
Another suggestion has been made that it is the Egyptian month Epiphi, which is written Abbi in later Aramaic. With the kalendar which is now before us, we may see how far this is possible. The limits of Abib, in order to have the full moon next after the vernal equinox, are that its first day shall be between 7 March and 4 April. And if the lunar month was named from the Egyptian month with which it most nearly coincided, the limits for the first day of Epiphi would be 2 1 February and 20 April. The dates of the month being at these limits are 1032 B.C. and 1280 B.C. Thus at the probable date of the Exodus, about 1220 B.C., Epiphi would most nearly coincide with Abib in case of a late Passover moon.
and Irenaeus keeps saying in Book Two that the Marcosians (or possibly the Valentinians) identify the Passion as having taken place in the twelfth month with the twelfth apostle:
They endeavour, for instance, to demonstrate that passion which, they say, happened in the case of the twelfth AEon, from this fact, that the passion of the Saviour was brought about by the twelfth apostle, and happened in the twelfth month. For they hold that He preached [only] for one year after His baptism. They maintain also that the same thing was clearly set forth in the case of her who suffered from the issue of blood. For the woman suffered during twelve years, and through touching the hem of the Saviour's garment she was made whole by that power which went forth from the Saviour, and which, they affirm, had a previous existence. For that Power who suffered was stretching herself outwards and flowing into immensity, so that she was in danger of being dissolved into the general substance [of the AEons]; but then, touching the primary Tetrad, which is typified by the hem of the garment, she was arrested, and ceased from her passion.[AH 2.20.1]
Got to think about how this all fits together. It certainly doesn't work in the traditional Jewsh system where Passover always falls in the first month. Epiphi is always the eleventh month of the Egyptian (Coptic) calendar. How do we get 'the twelfth month'? Did Passover in Jerusalem that year fall in the twelfth month of the Egyptian calendar? Questions, questions, questions ...
It's worth noting that the name of the twelfth month of Mesori comes from Mes-en-ra, an Ancient Egyptian word that means Birth of the Sun
