The Babylonian Calendar and the Bible by Sacha Stern

When ancient Israel fell under the dominion of great empires, its calendar was radically altered. This is because in ancient societies, time and calendars were mainly controlled by political rulers. So we find that in most of the Hebrew Bible, the months of the year are only numbered and hardly ever named; but after the Babylonian exile, in the books of Zechariah, Esther, Ezra, and Nehemiah, Babylonian month names suddenly appear and become quite frequent. The Babylonian months of Nisan, Sivan, Elul, Kislev, Tevet, Shevat, and Adar are used either on their own or alongside numbered months. Nisan, in the spring, is consistently equated in these books with the ‘first month’ of Exodus (Exod 12:2); Nisan, indeed, was the first month of the Babylonian calendar.

The use of Babylonian month names, which later became standard in the Jewish calendar, is hardly surprising in the context of the postexilic period. The Babylonian calendar originated in Babylonia (southern Iraq) in the early second millennium B.C.E., spread to the rest of Mesopotamia in the late second millennium B.C.E., and then became, in the first millennium B.C.E., the official calendar of the great empires of Assyria, Babylonia, and Persia, in use across the whole Near East. The Jews under Persian rule adopted it as their own calendar, as did many other peoples in the Persian Empire.

The Jews adopted not only Babylonian month names but also the entire Babylonian calendar. This calendar was lunar, with each month beginning at the sight of a new moon. Since twelve lunar months are approximately eleven days shorter than the solar year, the Babylonian calendar was intercalated (or evened out) every two or three years by the addition of a 13th month (usually by duplicating the 12th month, Adar, and less frequently by duplicating the sixth month, Elul). This allowed the lunar system to catch up with the sun and the seasons. This calendar may have been quite similar to the original Israelite one, which was most likely also lunar; indeed, this may have helped the Jews to adopt it without qualms.

That Jews of the postexilic period were using the official, imperial calendar to determine the dates of biblical festivals is evident, at least, from the “Passover Papyrus” from Elephantine (a Jewish colony in southern Egypt). This document indicates that in 419 B.C.E., Jews at Elephantine observed the festivals of Passover and Unleavened Bread during the first month of the Babylonian calendar, Nisan, in accordance with the Pentateuch’s prescription that these festivals be observed “in the first month” of the year.

This practice presumably continued right into the Hellenistic period, when the Babylonian calendar was still largely used for official purposes by the Aramaic-speaking peoples of the Near East. But after the Jewish Hasmonean state broke off from its Hellenistic Seleucid overlords in the mid-second century B.C.E., the Jews no longer had any reason to comply with the calendar of distant Babylon, and their calendar soon acquired distinct features. Although the Babylonian month names were retained (as in the books of Maccabees), the calendar was intercalated at different times (only the month of Adar, but not Elul, would be intercalated). Still, many Babylonian features remained central to the Jewish calendar, as the Talmud later remarked: “Rabbi Hanina said: the month names came up with them [with the exiles] from Babylon” (Jerusalem Talmud, Rosh HaShanah 1:2, 56d).

Sacha Stern, "Babylonian Calendar and the Bible", n.p. [cited 29 Nov 2022]. Online:


Sacha Stern

Sacha Stern
Professor, University College London

Sacha Stern is professor of Jewish Studies at University College London. He has widely researched the Jewish and other calendars and is currently directing several research projects on ancient and medieval calendars. His publications include Calendar and Community: a History of the Jewish Calendar, 2nd cent. BCE–10th cent. CE (Oxford University Press, 2001), Time and Process in Ancient Judaism (Oxford University Press, 2003), and Calendars in Antiquity: Empires, States, and Societies (Oxford University Press, 2012).

Of or relating to ancient lower Mesopotamia and its empire centered in Babylon.

A region in northern Mesopotamia whose kings ruled most of the ancient Near East in the 8th and 7th centuries B.C.E.

Ancient lower Mesopotamia, which for much of the second and first millenniums was the under the control of an empire centered in Babylon.

The period between 586 and 539 B.C.E., when the leaders and elite of Judea were exiled to Babylon. The exile ended when Cyrus of Persia defeated Babylon and allowed the Judeans to return home.

A territory controlled by a different nation, generally in separate geographic regions.

An island in the Nile River that housed a Judean military garrison in the Persian period.

A broad, diverse group of nations ruled by the government of a single nation.

general condition of living away from ones homeland or specifically the Babylonian captivity

migration of the ancient Israelites from Egypt into Canaan

Relating to the dynasty established by Simon Maccabeus that ruled Israel independently from 140-37 B.C.E.

A West Semitic language, in which most of the Hebrew Bible is written except for parts of Daniel and Ezra. Hebrew is regarded as the spoken language of ancient Israel but is largely replaced by Aramaic in the Persian period.

Of or relating to Greek culture, especially ancient Greece after Alexander the Great.

Relating to or associated with people living in the territory of the northern kingdom of Israel during the divided monarchy, or more broadly describing the biblical descendants of Jacob.

the ninth month of the Jewish calendar

Relating to the period in Judean history following the Babylonian exile (587–539 B.C.E.), also known as the Persian period, during which the exiles were allowed to return to Judea and rebuild the temple in Jerusalem.

The period in Judean history following the Babylonian exile (587–539 B.C.E.), also known as the Persian period, during which the exiles were allowed to return to Judea and rebuild the temple in Jerusalem.

A collection of rabbinic writings, mostly interpretations of the Hebrew Bible and the Mishnah (another rabbinic collection). There are two Talmuds, the Palestinian and the Babylonian, so called after the region in which each is believed to have been compiled. The Talmuds were likely composed between the third and the sixth centuries C.E.

the tenth month of the Jewish calendar

made without a leavening agent, such as yeast or baking powder

Exod 12:2

2This month shall mark for you the beginning of months; it shall be the first month of the year for you.

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