Why did the Hebrews not create their own calendar system instead of copying the pagan Babylonians'?

I find it interesting that they use a pagan calendar which often honours pagan gods. Why is this permitted?

A source for the claim that the Babylonian months honored pagan gods:

Tamuz - Hebrew Month

The name of the month was adopted from the Assyrian-Babylonian calendar, in which the month was named after one of the main Mesopotamian gods, Tammuz. This is referred to in Ezekiel 8:14.


Let's take a step back: the Hebrew calendar uses lunar months of either 29 or 30 days (for 354 days altogether). Now the Bible says that Passover should be in the spring, and if you keep having years of 354 days you'll keep sliding backwards until Passover won't be in the spring anymore, so every so often they'd add a leap month. Sure, other peoples may have had lunar calendars too, but nothing pagan or Babylonian per se here.

In the books of Moses, the months are simply called "first month", "second month", and so on. Passover is in the first month, Yom Kippur in the seventh. Nothing pagan or Babylonian here yet either.

Throughout the period of the Judges and First Temple (let's say very roughly from 3500 to 2500 years ago), we occasionally see the Bible use Hebrew names for some of the months (such as "Ziv"), instead of just the numbers.

The names that most of us are familiar with are, in fact, the Babylonian names. When the Jews were exiled to Babylon (roughly 2500 years ago) and came back (roughly 2400 years ago), the Jews chose to stick with Babylonian names for the months of the same calendar the Jews had been using for centuries.

So we didn't pick a Babylonian calendar; but we adopted Babylonian nicknames for the months.

The simplest explanation for that was to specifically commemorate the exodus from Babylon, to remind the people that we weren't always in Israel. Exile could happen, but so could redemption. (The book of Chronicles, for instance, ends on the high note of redemption from Babylon.)

  • 2
    The question didn't mention the names of the months but the calendar itself. For instance, why did the Hebrew calendar borrow the 'leap-month' from the Babylonian one? See for instance the article "Intercalation and the Hebrew Calendar" at jstor.org/stable/1516201 Your suggestion that we "didn't pick up a Babylonian calendar" is so oversimplified as to be practically untrue. "We heavily borrowed an identical lunisolar calendar from the Babylonians" is somewhat closer to the truth. Indeed many scholars believe prior to exile the Hebrews had a purely solar calendar,but see the article
    – Curiouser
    Sep 27 '11 at 15:24
  • 2
    @Curiouser the answer is actually quite accurate (other than that not all the names are Babylonian). Even before the exile the Hebrew calendar was lunisolar, all the talk wrt sanctifying the months etc is heavily tilted towards lunarity.
    – AviD
    Sep 28 '11 at 11:03
  • Cf. judaism.stackexchange.com/q/43296
    – msh210
    Jul 10 '14 at 20:18

The Babylonian calendar wasn't adopted exactly as it was, but the names of the months were. This was recognized by the Sages in the Gemara, Yerushalmi Rosh Hashana 1:2.

Why the Jews adopted these Babylonian names is a good question. In fact, it seems like the Jews did have their own ancient names for the months, such as 'Ziv' and 'Bul', which are mentioned in Kings I 6:37-38, but weren't used by the time of destruction.

  1. Ramban (Shemos 12:2) says that we adopted the Babylonian/Persian names as commemoration of the fact that God took us out of those countries (and brought about a smaller redemption from those exiles with the building of the Second Temple). This is parallel to the command regarding the new month and setting up of the calendar that came about with the redemption from the Egyption exile (see there, in Shemos/Exodus ch. 12). This reason (in slightly different forms) is also given by Rabbeinu Bachya and the Abarbanel in their commentaries there, as well as by R. Yosef Albo in Sefer HaIkarim 3:16.

  2. R. Yerucham Fishel Perlow (Sefer Mitzvos of Rasag, end of Aseh 56) seems to say that we shouldn't read to much into this practice; it was borne merely out of convenience that the Jews were in Babylonia, so they used Babylonian names, and it was just easier to keep those names even after leaving. (In fact, historically speaking much of the Jewish people remained in Babylonia anyway, and it was probably easier if everyone used the same dating system)

  3. R. Yaakov Kamenetsky (Emes L'Yaakov Shemos 12:2) has almost the opposite explanation: the Babylonian names of the months were kept when the Jews moved from Babylonia/Persia to Israel to remind them that this redemption was incomplete. (This relates to a fascinating idea, discussed by the Beis Halevi as well, that the Jewish people knew that the Second Temple would be incomplete and temporary from the start)

  4. Benei Yissaschar (R. Tzvi Elimelech of Dinov, on Nissan 1:6-7) states that the names of the month were actually of Jewish origin, but weren't written down or put into common use until the time of the Babylonian exile (for whatever mystical reasons). This is quoted by the Tzitz Eliezer 8:8:1:5

(These were meant to be responses to the question of why this was done in the first place. However, several commentators deal with a related question: how could this be allowed, when the Torah indicates, according to the aforementioned Ramban, that the months must be named according to their number from Nisan. This is dealt with by the Ritva in Rosh Hashana 3a, Tiferes Yisrael of the Maharal ch. 64, and in a few more recent books as well)



So why did we begin to use these names? Why didn't we stick with the Biblical practice of referring to months by their number?

Nachmanides suggests that this is consistent with Jeremiah's prophecy: "Therefore, behold days are coming, says G‑d, and it shall no longer be said [by one who wishes to pronounce an oath], 'As G‑d lives, who brought up the children of Israel from the land of Egypt,' rather, 'As G‑d lives, who brought up the children of Israel from the northland [Babylon]...'"

The original system was to count months in numeric order starting from the first month. Thus, any time a person mentioned a month he was in effect recalling the Exodus from Egypt—for now we are in, say, the sixth month—six months since the month of the Exodus. Thus the numeric naming served as a constant reminder of our deliverance from Egypt.

After we were delivered from Babylonian captivity, however, we started using the names that we came used to using in Babylon. And now, these names served to remind us that G‑d has redeemed us from this second exile.


the Hebrews do have their own calendar.you just haven't been taught it. It was given to Enoch before the flood and Moses after the flood. Book of Enoch ch 72 and book of jubilees ch 6:23-38. 364 day calendar.52 Sabbaths Perfectly 1st day of the new year starts on a sunday. last day of the year ends on a Sabbath.theres noway you can err in this calendar.just count 52 sabbaths

  • I don't know what is written in the sources that you cite, but our calendar very different from what you suggest.
    – jutky
    Oct 4 '14 at 22:13
  • Could you provide some sources? Is this distinct from the calendar in use by Ethiopian Jews? Jul 28 '16 at 5:08

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