Who controls the Hebrew calendar? Today, we take for granted the setting of the holy days and commemorations in the Jewish year. We do not dispute the date for Rosh Hashana or the Tenth of Tevet – we receive a Hebrew calendar from a Judaica shop or a Jewish funeral chapel at the beginning of the Jewish year and we display it our homes. We know the date for the new month, each holiday, and each fast day. We take it for granted that a religious authority set these dates “in stone” a long time ago.

Yet, this certainty regarding the cycle of the holidays in a set calendar did not always exist. Before Hillel II, the leader of the Jewish community in the Land of Israel under Roman rule in the fourth century CE who introduced the fixed Jewish calendar, there were fierce disputes among Jews regarding the correct calculation for the setting of holidays and the New Moon.

The debate over the setting of the liturgical calendar was central to the dispute between the community that produced the Dead Sea Scrolls and the priestly establishment in Jerusalem more than two millennia ago.

The Qumran scroll scribes based their liturgical calendar on the solar cycle. The Temple priests in Jerusalem based their determination of the date of the holidays on a lunar calendar (with adjustments to make sure that each holiday was set for its appropriate season in the agricultural cycle).

The Dead Sea Scroll community considered null and void the sacrifices of the priests in Jerusalem because, in their own setting of the calendar, the Temple priests were bringing sacrifices for the holidays on the wrong days. If the Jerusalem priests brought sacrifices for the Succot pilgrimage, the Qumran scribes considered the sacrifices invalid because the priestly establishment followed the wrong calendar.

This was certainly an issue of ritual, dates and times. But it was also a dispute over the efficacy of the cult and the issue of religious authority.

Even the rabbis, in the epoch following the Roman Empire’s destruction of the Jerusalem Temple in 70 CE, were disputing among themselves regarding the setting of the holidays in the Jewish cycle of the year. According to rabbinic legend, Rabban Gamaliel II, the successor of Yohanan Ben-Zakkai as leader of the Jews in Judea under Roman domination, publicly disgraced Rabbi Joshua ben Hananiah over a calendar dispute.

Due to differences concerning the date for the New Moon – before the fixed calendar of Hillel II the determination of Rosh Chodesh was based on human observation – each rabbi had a different date for Yom Kippur. Gamaliel ordered Joshua to “appear before me with your staff and your money on the day which according to your reckoning should be the Day of Atonement.”

Joshua did so. The rabbinic colleagues of the humiliated Joshua were so angry over Gamaliel’s unjust exertion of his authority that they removed Gamaliel temporarily from his leadership position. Again, the setting of the calendar was not just an issue of mathematical calculation.

It was an issue of power.

Six hundred years after Hillel II fixed the calendar, there were still debates concerning the dates of the holidays in the Jewish liturgical year. In 922, Aaron Ben-Meir, head of the Jerusalem academy, announced that Passover would fall on Sunday, and not on Tuesday as accepted according to the calendar of the dominant Jewry in Babylonia.

Saadia Gaon, the greatest philosopher and halachic authority in the history of Babylonian Jewry, found himself in the center of what threatened to be a major schism in the Jewish world. In the end, Saadia and the Babylonians were the victors in the battle with the rabbis of Israel. That this issue was still heated centuries after the Jewish liturgical calendar had been fixed is a reflection of the power of those that control the setting of the calendar.

Authority over the calendar meant ultimate authority over the Jewish people.

How religious authorities determined the setting of the holidays in Jewish history – and their disputes over the setting of those days – exemplify the flexibility of the Hebrew calendar. While in modern times the Jewish liturgical calendar seems to be “set in stone,” the reality is that historically the calendar has been marked by much fluidity.

Today, the calendar disputes no longer center on the setting of the holidays and the New Moon. The critical issue Jews face now is the incorporation of new holy days or commemorations into the liturgical calendar. This is not just a 21st-century issue. The rabbis mandated many holy days and fasts not mentioned in the Torah: Hanukka, Purim, Tisha Be’av, Lag Ba’omer, Simchat Torah and others.

In the past 1,000 years, however, no new celebrations or commemorations have been added to the liturgical calendar. Of course, Yom Hashoah (Holocaust Remembrance Day), Yom Ha’atzmaut (Israel Independence Day), and Yom Yerushalayim (Jerusalem Reunification Day) all appear on the Jewish liturgical calendars that we display in our homes. But are these special days truly religious holidays and religious commemorations? Are they not mandated by the secular authority of the Israeli Knesset and not by rabbinic authority of the Sanhedrin? Are these days part of the calendar of all of Jewry? Are they truly universal for the Jewish people? These are critical questions we must ask if we are to determine whether the Hebrew calendar can remain a flexible, living and vital phenomenon that can adapt to change – or an inert, dead letter that does not reflect Jewish life as it is lived in our new millennium.

The writer is rabbi of the Beth Ami Congregation in Boca Raton, Florida.

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