Dead Sea Scrolls mystery: Israeli researcher proposes solution to Qumran sect's 364-day calendar

A new study by Tel Aviv University researchers suggests a solution to a long-standing mystery surrounding the Dead Sea Scrolls: the Qumran sect's unique 364-day calendar. For decades, scholars debated whether this calendar was ever practically used or merely a theoretical construct.

In a study published in the Tarbiz Quarterly for Jewish Studies, Professor Eshbal Ratzon proposes that the 364-day calendar was indeed employed by the sect in its formative years. She further argues that this calendar might have been a central factor in the conflict that led the sect to retreat to the desert.

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the Qumran sect’s unique calendar, has been proposed by researchers from Tel Aviv University (TAU).

The significance of calendars and astronomy to the Qumran community is underscored by the fact that nearly 20 of the scrolls found at Qumran focus on these subjects. The Book of Jubilees, a key text in the Qumran library, strongly criticizes the prevailing lunar calendar and presents the 364-day calendar as divinely ordained by Moses.

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For decades, scholars have wondered if Qumran’s 364-day year calender had ever been used in practice.

While mainstream Judaism during the Second Temple period followed a lunisolar calendar, the Qumran sect adhered to a 364-day system. This calendar, perfectly divisible by seven, ensured that every year consisted of 52 full weeks, meaning holidays consistently fell on the same days of the week. This regularity symbolized the perfect divine order for the sect.

Furthermore, the 364-day calendar served as a symbol of rebellion against the political and religious authorities in Jerusalem, who dictated significant dates for Jewish life. The Qumran sect believed these dates were predetermined by God at Creation and should not be altered by human intervention.

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in a study recently published in the Tarbiz Quarterly for Jewish Studies, TAU Prof. Eshbal Ratzon suggested that Qumran’s 364-day year calender had indeed been used by the sect in its early years.

However, Ratzon suggests the calendar was likely abandoned for two primary reasons. Firstly, the one-and-a-quarter-day discrepancy between the 364-day calendar and the astronomical year accumulated rapidly, causing festivals to shift significantly relative to the seasons. After two decades, festivals could shift by nearly four weeks, and over several decades, celebrations intended as agricultural events would occur in the wrong seasons. This posed a fundamental problem for a community that viewed its festivals as intrinsically linked to the harvest and the changing seasons.

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almost 20 of the scrolls found in Qumran deal with calendars and astronomy, a number proving the importance the topic held with the community.