Of course, even before the acquisition of the Temple Scroll, we knew about the solar calendar used by the Essenes, which contrasted with the lunar calendar practiced by normative Judaism. The Essenes' solar calendar was divided into four sections consisting of three thirty-day months, plus one additional day. Thus the Essene year contained 364 days, divided into twelve thirty-day months, plus four intercalated days inserted at the end of each three-month group. (In the course of years, this calendar would need additional intercalated days--or leap years--to maintain the same seasons, but we have no information, for the time being on how the Essenes did this.) Using this calendar, however, results in holidays always falling on the same day of the week.

I have already mentioned the many "new"--or previously unknown--holidays described in the Temple Scroll, including three new (and one well-established) "first fruits" festivals. The Essenes reckoned the date on which each of these festivals began by counting fifty days after a particular Sabbath (counting the day of the preceding restival as the first day of the new counting), with the result that these festivals alwasy began on a Sunday. Sunday thus begins to appear as a more important date.

Yigael Yadin, Understanding the Dead Sea Scrolls p 109.