Zoroastrian Calendar - Development of A 365-day Calendar

Development of A 365-day Calendar

Five significant stages seem to have occurred in the introduction of a stable 365-day calendar. Mary Boyce has observed that contemporary scholars are divided on whether this 365-day calendar was in fact preceded by a 360-day calendar of Zoroastrian observances.

First: A 365-day calendar was introduced during the reign of the Sasanian emperor Ardashir I (226-241 CE). The names of months and of days of the month that had been used in Achaemenian times remained unaltered; the five additional days were inserted after the twelfth month. These five days were named Gatha or Gah days, after the ancient Avesta hymns of the same name. In 226 CE, 1 Frawardin and the New Year celebration of Nawruz had drifted to 1 October. The older custom of counting regnal years from the monarch's coronation was reinstated.

Second: After 46 years (226-272 CE), with 1 Frawardin now on 19 September, another calendar reform was implemented by Ardashir's grandson Hormazd I (272-273 CE). It seems that during the first year after implentation of the Gatha days, the population had not universally adopted the new dates for religious festivals, resulting in "official" celebrations takings place five days later than popular celebrations. In later years the population had observed the Gatha days, but the original five-day discrepancy persisted. Hormazd's reform was to link the popular and official observance dates to form continual six-day feasts. Nawruz was an exception: the first and the sixth days of the month were celebrated as different occasions. Lesser Nawruz was observed on 1 Frawardin. 6 Frawardin, became Greater Nawruz, a day of special festivity. Around the 10th Century CE, the Greater Nawruz was associated with the return of the legendary king, Jamsed; in contemporary practice it is kept as the symbolic observance of Zoroaster’s birthday, or Khordad Sal.

Third: A major reform of the religious calendar was implemented some time between 399 and 518 CE. The names of the days and months were unaltered, but Nawruz would now be celebrated on the first day of Adur, hitherto the ninth month of the calendar. Other religious festivals were shifted to maintain their relative position to Nawruz. Mary Boyce has argued that, as part of this reform, the six-day festivals were compressed to five days. The major feasts, or gahambars, of contemporary Zoroastrian practice, are still kept as five-day observances today.

Fourth: By the reign of Yazdegird III (632-651 CE), the religious celebrations were again somewhat adrift with respect to their proper seasons. Therefore in 632 CE, the new year due to be celebrated on June 21 was brought ahead by the device of omitting that year's Gatha days; Nawruz was therefore kept on June 16. Most Persian Zoroastrians accepted and used this new calendar. By the 9th century, the Zoroastrian theologian Zadspram had noted that the state of affairs was less than optimal, and estimated that at the time of Final Judgement the two systems would be out of sync by four years.

Fifth: In 1006 CE, the month Frawardin had returned to the correct position so that 1 Frawardin coincided with the Northern vernal equinox. The religious festivals were therefore returned to their traditional months, with Nawruz once again being celebrated on 1 Frawardin.