By contrast, the 364-day calendar was perfect,” they write in the Journal of Biblical Literature. “Because this number can be divided into four and seven, special occasions always fall on the same day. This avoids the need to decide, for example, what happens when a particular occasion falls on the Sabbath, as often happens in the lunar calendar. The Qumran calendar is unchanging, and it appears to have embodied the beliefs of the members of this community regarding perfection and holiness.”

Ratson and Ben-Dov found that the scroll lays out the most important dates in the Qumran sect’s 364-day calendar, including the festivals of New Wine and New Oil, which are not mentioned in the Bible. It also reveals for the first time the name given to the special days on which the sect would celebrate the transition between seasons, four times a year. The days were referred to as “Tekufah”, which translates as “period”.