For scholars of the Dead Sea Scrolls, the mystery of the 364-day version of the solar calendar discussed extensively in the scrolls found in Qumran has remained an unsolved puzzle for decades. Was this flawed model of timekeeping, which lost 1.25 days every year, actually used in practice, or was it just a theoretical model?

New research published by Prof. Eshbal Ratzon of the Department of Jewish Philosophy and the Cohn Institute for the History and Philosophy of Science and Ideas at Tel Aviv University suggests a new approach: The calendar, which sat at the crux of a bitter dispute between the Qumran sect and the rabbinic Pharisee community some 2,100 years ago, was indeed used in Qumran, but was later abandoned when it drifted too far from the seasonal flow and political relations allowed for a smooth transition.

The history of the strange calendar has to be understood in the context of the acrimony between the mainstream Pharisees and the Essenes and Sadducee movements at the time, Ratzon told The Times of Israel in a phone discussion. Her paper was recently published in the Tarbiz Quarterly for Jewish Studies.

“There were several halachic disputes between the two sides at that time, including issues related to purity in the Temple, but most likely, they were all built around political and personal rivalries,” Ratzon said. “Many arguments can be resolved when there are good intentions, but in this case, they clearly wanted to split, and these issues were framed as the cause for separation.”

By the time the Qumran sect, which many scholars associate with the Essene community, settled in caves in the desert near the Dead Sea, astronomers in Egypt and other civilizations had already established that the solar year was at least 365 days, even if they didn’t yet add a day every four years to account for the extra six hours in the Earth’s annual journey around the sun.

(Israelites tracked their lifecycles according to the lunar calendar, in which 12 months equate to about 354 days and nine hours, but scholars had already developed a 19-year cycle of leap years to ensure that seasonal holidays remained broadly on time.)

But a 364-day year fit better into what Qumran elders may have seen as a perfect divine order, Ratzon said. That number divided evenly into seven, and would thus allow every date to fall on the same day of the week every year. The first day of Passover, for example, would always fall on a Wednesday, simplifying scheduling challenges (and possibly shedding light on a Talmudic discussion about whether the counting of the Omer begins on Sunday or on the second day of the holiday).

The problem with following a 364-day........

© The Times of Israel