Hebrew In Israel | Calendars – Learn Torah

enoch calendar, hebrew calendar, israel calendar, jewish calendar, solar calendar, torah calendar,

Hebrew In Israel | Calendars – Learn Torah


Calendars have always been a struggle for mankind.  From the earliest calendars to the modern ones, man has always tried to calculate time and create an ideal way of using it.  Here are two short discussions about calendars.

The Rabbinic Calendar

Every once in a while, I get challenged by different people about the Jewish calendar and the influences from the outside.  A common misconception is that the old calendar used in the 2nd temple is not the same as the one used till the 4th century.  However, rabbinic Judaism used actual sightings of the moon for a long time, and we even have some evidence that sightings were conducted till the 10th century. 

The record in the Mishna and Talmud on Rosh-Hashanah clearly indicates the use of actual sightings, and gives different calculations to predict the actual visible new crescent.  Unfortunately, due to misunderstandings, people keep on associating the new moon sighting to Karaites, when in fact this was a pan Jewish practice.  The changes happened when no adjustments were made, and only the calculation was used.  This seems to be a problem which developed in Babylon during Medieval times where the method of pre-calculation was not used correctly. 

According to research, the calculation known as “Sod Ha’ibur” (סוד העיבור) was revealed by Hillel the 2nd in the 4th century out of a need to keep the diaspora on the same time as the land.  However, due to the rising competition between the two centers, and the decline in power of the Yeshiva of the land of Israel, the powers in Babylon became the dominant deciding body.  This seems to have caused the incorrect idea that conjunction is the new moon, and the forsaking of actual sighting. 

This reached a point where R. Se’adya Gaon declared in his Siddur that the calculation is the original, and that the new moon has not been seen on the day of Yom Teru’ah in a long time (Otzar Hageonim, Rosh Hashanah pp.33-35).  He rendered the calculation as more important than the sighting, something which might also be understood in the letter exchange with R. Ya’akov Ben-Meir, the head of the Yeshiva in Israel at the time.

Another argument presented is that the rabbinic calendar was Babylonian due to the use of Babylonian names to the months.  Though the use of the names is true, the fact is that this was due to administrative use by the Babylonians and Persians, and did not affect the biblical calendar.  This can be seen in the fact that the dates still fall at the original times, and all that changed is the names.  We can see influences even in the bible with late books such as Ezra-Nehemiah using these names.  We can even go back to the 1st temple and the mentioning of Phoenician names such as Bul (1Kings 6:38) and Eitanim (1Kings 8:2) in the book of Kings.

The Enoch Calendar 

I just finished an article on the 364-day sun calendar as found in the Book of Jubilees and Enoch.  The writers Dr. Jonatan Ben-Dov and Prof Wayne Horowitz demonstrate that the calendar had its origins in the administrative calendar used in Mesopotamia.  The 364-day calendar was created in detachment from the Lunar-Solar calendar to accommodate the subjects of running the economic system used in the kingdoms.  This calendar ignored the lunar cycle, and created an artificial 12-month calendar with exactly 30 days for each month.  This calendar seems to have been imported into the Jewish world and was incorporated into the writings of Pseudo Enoch and Jubilees.

One of the important points raised in the paper is that this 364-day calendar really surfaces in Mesopotamia around the 7th century, making it a calendar which appears at about the same time as the exiles from Israel.  It seems to me that it was used as an administrative tool by the exiles and imported by the different empires.  Later on, this calendar was mistaken by later generations as the “original” calendar by the late writers of these books during the 3rd and 2nd centuries BCE. 

The writers demonstrate that the calendar of 364 days is parallel to the Mesopotamian time calculation in more than just the schematic idea of time division of 12×30-364, but also in several astronomical principles.

  1. Both calendars are trying to improve on the 360-day calendar used in Mesopotamia
  2. Enoch draws many parallels to Mesopotamian heroes and resembles them greatly.  This is a diversion from the common biblical practice of presenting parallel heroes as different and more human.
  3. The Enoch calendar calculates the day and night the same way the Mol-Appin does, dividing the time to 18 parts.  During the equinoxes, the time ratio is 1:2 which does not fit the length of time in Israel and is the same time ideal of the Mesopotamian document.
  4. Both documents try to use a star movement based idea of 12 constellations as an attempt to reconcile with the seasons and the Lunar-Solar civil calendar which was common in the Fertile Crescent.
  5. Both calendars assign a guardian to the 4 periods dividing the year.  The Mesopotamian gives the responsibility to different gods, while Enoch to angels.   
  6. Both use the four corners of the winds and connect them to the movements of the illuminants in the sky.

The writers go over more issues which appear in other documents found in the Dead Sea Scrolls, but the main issue is the very clear link in type of knowledge and method of time calculation used in both documents.  The conclusion of the writers, which is a common understanding, is that the calendar used in Enoch is mostly an ideal calendar, but in real practice it will create a time difference which will result in a month difference in the larger cycle of time.  This difference will create a month difference in 25 years, causing the feasts to move, causing Passover to be in the summer at one point. 

It does not seem this calendar had the method of adding an extra month every three years or so, and no mention of such a thing is found in the different texts.  Adding a month was a common practice in all Lunar-Solar calendars, and was needed to keep feasts and festivals at their agricultural appointed time.

“The 364-day year in Mesopotamia and Qumran”, Megilot 1, Bialik Institute 2003, pp.3-26


Larry Hardison

October 22, 2017 at 9:14 pm

Have you done, or will you, do an article on the observed (New Crescent Moon) calendar and supporting information?

Rick Radavich

October 24, 2017 at 5:30 am

Yoel, here is an interesting paper on the intercalation of the 364 day calendar. (The stories from Jubilees) https://www.academia.edu/19936654/The_364-Day_Calendar_of_King_Solomon_and_the_Divided_Monarchy_of_Israel_and_Judah

Is there an actual source by Hillel II for his calculation? I see many references to him, but no actual source given. The DSS contain over 70 references to the 364 day calendar all written during the 2nd temple period. Are there any Hebrew based lunar calendars from before the Temple’s destuction in 70 CE? that are not in the DSS? While there appear to be dates that would fit a luni solar calendar reckoning, I have yet to find a source that a lunar based calendar could be reconstructed from.

Anna Siebert

October 29, 2017 at 2:32 pm

A friend told me about you.
Would you be so kind to send me new posts by email?
Thank you sincerely
Anna Siebert


    October 30, 2017 at 2:48 pm

    Hello, Anna! You have been subscribed to our blog and will receive new teachings as they are published. Thank you!

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