The Priestly 364-Day Solar Calendar
The Enoch/Zadok calendar is a 364-day solar calendar preserved in the Dead Sea Scrolls and the Book of Enoch. The scrolls were found at Qumran, near the Dead Sea, and the texts themselves reflect a community in sharp conflict with the Jerusalem temple establishment — though who exactly that community was remains genuinely uncertain.
The dominant scholarly view identifies the scroll authors with the Essenes, a sect described by Josephus and Philo as living apart, holding goods in common, and rejecting the Jerusalem priesthood. The identification is plausible and widely accepted, but it is an inference — no scroll says "we are the Essenes." The Damascus Document also suggests that related communities lived in towns across Judea, not only at Qumran, which complicates any single tidy label.
What the texts do say clearly is that their authors considered themselves "Sons of Zadok" — though whether this was a literal genealogical claim or a symbolic title for the faithful remnant is itself unclear. They used Isaiah 40:3 ("prepare the way of the LORD in the wilderness") as a self-description, and they condemned the Jerusalem calendar in strong terms. The Second Temple used a lunisolar calendar — lunar months periodically adjusted to the solar year, with feast dates set by moon sighting — and the scroll authors regarded this whole system as a corruption of the true order. In their view, the Jerusalem feasts fell on the wrong days, observed by priests with no legitimate claim to the office.
Unlike the lunar temple calendar, the Zadok calendar is purely solar with exactly 364 days, divided into four equal quarters of 91 days each. Because 364 is exactly divisible by 7, every date falls on the same day of the week every year — a feature the Qumran priests considered essential for orderly, incorruptible worship.
Key texts: 1 Enoch 72–82 (the Astronomical Book), Jubilees 6:23–38, and the Songs of the Sabbath Sacrifice from Qumran.
The calendar is anchored to the fourth day of creation (Genesis 1:14–19), when God created the sun, moon, and stars as signs for seasons, days, and years. Wednesday is the fourth day of the week (counting from Sunday as day one), so the priestly reckoning places the year's beginning — 1 Aviv — on Wednesday.
In practice, 1 Aviv is set to the first Wednesday on or after the spring equinox (approximately March 20). This anchors the solar calendar to the astronomical year while preserving the Wednesday start.
Because the year is exactly 364 days (52 weeks × 7), every date advances by zero weekdays from one year to the next. The feasts are therefore permanently fixed to specific weekdays:
Proponents argue this fixed structure is precisely what Torah intended — worship that never conflicts with the Sabbath and that any family anywhere can predict without priestly calculation.
The year is divided into four quarters of 91 days each, with three months per quarter:
The extra day in the third month of each quarter (31 instead of 30) ensures the next quarter's first month begins back on Wednesday. This produces exactly 52 Sabbaths per year — no more, no fewer.
The four quarters correspond to the four seasons: Spring (Aviv–Sivan), Summer (Tammuz–Elul), Autumn (Tishri–Kislev), and Winter (Tevet–Adar).
The true solar (tropical) year is approximately 365.25 days, leaving the 364-day calendar about 1.25 days short each year. Over seven years this accumulates to nearly nine days of drift.
The Dead Sea Scrolls and Jubilees hint at an intercalation system — extra days inserted periodically to re-synchronize the calendar with the sun — but the exact mechanism is not fully preserved in surviving texts and remains debated among scholars.
This site currently displays the ideal 364-day cycle anchored annually to the spring equinox, which sidesteps the long-term drift question by re-anchoring each year independently.
Anno Mundi (Latin: "in the year of the world") counts years from the traditional date of creation. This site uses the offset Gregorian year + 3925, placing creation at 3925 BCE — a figure derived from the chronology of the Hebrew scriptures as reckoned in certain ancient traditions.
This differs from the rabbinic AM reckoning (Gregorian + 3760), which follows a different creation chronology. The Zadok/Enoch tradition and the Book of Jubilees operate within a Jubilee cycle framework (49-year periods) that produces a somewhat different total.