The Bahá'’ calendar seems to be a modification of the modern Gregorian-Iranian calendar (called Fasli), which, at least in its classic form, was certainly well-known to Muhammad.
Why did Muhammad not prefer the solar Iranian calendar to the Arabian lunar calendar? Perhaps for the same reason that the Báb chose his nation's traditional calendar.
The Báb took for his calendar the ancient Iranian national calendar, but adjusting the number of days in each month from 30 to 19. He kept the Iranian "Naw Ruz", the "intercalary days", and "feasts" (there are 21 in the Iranian calendar). The Iranian calendar identifies days and months with spiritual beings, whereas the Bahá'’ calendar identifies days and months with spiritual qualities.
Bahá'’s are generally given to the misconception that their calendar was born anew for the New Era. This is a part of their doctrine of "progressive revelation", which explains that each new "Manifestation of God" brings a new calendar. Mostly it amounts to the founders of each new religion resetting their clocks, so to speak. Bahá did no such thing, in spite of the purported greatness of the date of his declaration.
When the Báb based his calendar on his national calendar, it was no act of world calendar unification, such as a new 10-month calendar might be regarded, but simply an act of patriotism.
More information on the Zoroastrian calendar can be found at the Zoroastrian Page.
Information on Zoroastrianism can also be found at Twilit Grotto.
The following data was acquired from a now-defunct web site. Similar data is available on Twilit Grotto's Zoroastrian religious calendar page.
Each month and each day of the religious calendar is presided over by a spiritual being; special prayers (from the Khorda Avesta) are observed in honor of that spiritual being. Days where the same spiritual being presides over both month and day (marked with * in the table below) are particularly sacred.
Watches (gahs) of the day:
Many prayers are altered according to the time of day.
- Hawan (sunrise to noon)
- Rapithwin or Second Hawan (noon to 3 p.m.)
- Uzerin (3 p.m. to sunset)
- Aiwisruthrem (sunset to midnight)
- Ushahin (midnight to sunrise)
Names of the days
(and corresponding dates of observance per Fasli calculations):
Mah (Month) Roz (day) Frawardin Ardwahisht Hordad Tir Amurdad Shahrewar
Ohrmazd Mar21 Apr20 May20 Jun19 Jul19 Aug18 Vohuman Mar22 Apr21 May21 Jun20 Jul20 Aug19 Ardwahisht Mar23 r Apr22 * May22 Jun21 Jul21 Aug20 Shahrewar Mar24 Apr23 May23 Jun22 Jul22 Aug21 * Spandarmad Mar25 Apr24 May24 Jun23 Jul23 Aug22 Hordad Mar26 Apr25 May25 * Jun24 Jul24 Aug23 Amurdad Mar27 Apr26 May26 Jun25 Jul25 * Aug24 Dae-pa-Adar Mar28 Apr27 May27 Jun26 Jul26 Aug25 Adar Mar29 Apr28 May28 Jun27 Jul27 Aug26 Aban Mar30 Apr29 May29 Jun28 Jul28 Aug27 Khwarshed Mar31 Apr30 g May30 Jun29 g Jul29 Aug28 Mah Apr1 May1 May31 Jun30 Jul30 Aug29 Tir/Tishtar Apr2 May2 Jun1 Jul1 * Jul31 Aug30 Goshorun Apr3 May3 Jun2 Jul2 Aug1 Aug31 Dae-pa-Mihr Apr4 May4 Jun3 Jul3 Aug2 Sep1 Mihr Apr5 May5 Jun4 Jul4 Aug3 Sep2 Srosh Apr6 May6 Jun5 Jul5 Aug4 Sep3 Rashnu Apr7 May7 Jun6 Jul6 Aug5 Sep4 Frawardin Apr8 * May8 Jun7 Jul7 Aug6 Sep5 Warharan Apr9 May9 Jun8 Jul8 Aug7 Sep6 Ram Apr10 May10 Jun9 Jul9 Aug8 Sep7 Wad, Gowad Apr11 May11 Jun10 Jul10 Aug9 Sep8 Dae-pa-Den Apr12 May12 Jun11 Jul11 Aug10 Sep9 Den Apr13 May13 Jun12 Jul12 Aug11 Sep10 Ard Apr14 May14 Jun13 Jul13 Aug12 Sep11 Ashtad Apr15 May15 Jun14 Jul14 Aug13 Sep12 g Asman Apr16 May16 Jun15 Jul15 Aug14 Sep13 Zam Apr17 May17 Jun16 Jul16 Aug15 Sep14 Mahraspand Apr18 May18 Jun17 Jul17 Aug16 Sep15 Anagran Apr19 May19 Jun18 Jul18 Aug17 Sep16
Mah (Month) Roz (day) Mihr Aban Adur Dae Bahman Spendarmad
Ohrmazd Sep17 Oct17 Nov16 Dec16 * Jan15 Feb14 Vohuman Sep18 Oct18 Nov17 Dec17 Jan16 * Feb15 Ardwahisht Sep19 Oct19 Nov18 Dec18 Jan17 Feb16 Shahrewar Sep20 Oct20 Nov19 Dec19 Jan18 Feb17 Spandarmad Sep21 Oct21 Nov20 Dec20 Jan19 Feb18 * Hordad Sep22 Oct22 Nov21 Dec21 Jan20 Feb19 Amurdad Sep23 Oct23 Nov22 Dec22 Jan21 Feb20 Dae-pa-Adar Sep24 Oct24 Nov23 Dec23 * Jan22 Feb21 Adar Sep25 Oct25 Nov24 * Dec24 Jan23 Feb22 Aban Sep26 Oct26 * Nov25 Dec25 Jan24 s Feb23 Khwarshed Sep27 Oct27 Nov26 Dec26 Jan25 Feb24 Mah Sep28 Oct28 Nov27 Dec27 Jan26 Feb25 Tir/Tishtar Sep29 Oct29 Nov28 Dec28 Jan27 Feb26 Goshorun Sep30 Oct30 Nov29 Dec29 Jan28 Feb27 Dae-pa-Mihr Oct1 Oct31 Nov30 Dec30 * Jan29 Feb28 Mihr Oct2 * Nov1 Dec1 Dec31 g Jan30 Feb29 Srosh Oct3 Nov2 Dec2 Jan1 Jan31 Mar1 Rashnu Oct4 Nov3 Dec3 Jan2 Feb1 Mar2 Frawardin Oct5 Nov4 Dec4 Jan3 Feb2 Mar3 Warharan Oct6 Nov5 Dec5 Jan4 Feb3 Mar4 Ram Oct7 Nov6 Dec6 Jan5 Feb4 Mar5 Wad, Gowad Oct8 Nov7 Dec7 Jan6 Feb5 Mar6 Dae-pa-Den Oct9 Nov8 Dec8 Jan7 * Feb6 Mar7 Den Oct10 Nov9 Dec9 Jan8 Feb7 Mar8 Ard Oct11 Nov10 Dec10 Jan9 Feb8 Mar9 Ashtad Oct12 g Nov11 Dec11 Jan10 Feb9 Mar10 Asman Oct13 Nov12 Dec12 Jan11 Feb10 Mar11 Zam Oct14 Nov13 Dec13 Jan12 Feb11 Mar12 Mahraspand Oct15 Nov14 Dec14 Jan13 Feb12 Mar13 Anagran Oct16 r Nov15 Dec15 Jan14 Feb13 Mar14
* = Name day feasts r = Rapithwina begins Mar 23 ends Oct 16 s = Sada g = Gahambars ('feasts'): 1992-5 1996-9 Maidyozarem ('mid-spring' feast): F: Apr30-May4 Apr30-May4 S: Oct2-6 Oct1-5 Q: Sep2-6 Sep1-5 Maidyoshahem ('mid-summer' feast): F: Jun29-Jul3 Jun29-Jul3 S: Dec1-5 Nov30-Dec4 Q: Nov1-5 Oct31-Nov4 Paitishahem (feast of 'bringing in F: Sep12-16 Sep12-16 the harvest'): S: Feb15-19 Feb14-18 Q: Jan16-20 Jan15-19 Ayathrem ('bringing home the herds'): F: Oct12-16 Oct12-16 S: Mar15-19 Mar14-18 Q: Feb15-19 Feb14-18 Maidyarem ('mid-year'/winter feast): F: Dec31-Jan4 Dec31-Jan4 S: Jun4-8 Jun3-7 Q: May5-9 May4-8 Hamaspathmaidyem ('coming of the F: Mar16-20 Mar16-20 whole group [of farohars]', S: Aug18-22 Aug17-21 feast of All Souls): Q: Jul19-23 Jul18-22 - Ahunawad - Ushtawad - Spentomad - Wohukhshathra - Wahishtoisht (Parsi Mukhtad adds 5 days to beginning) Noruz ('New Year's Day') F: Mar21 Mar21 S: Aug23 Aug22 Q: Jul24 Jul23
NOTES:
The religious calendar is a matter of some controversy among Zoroastrians. The oldest Zoroastrian calendar ('Old Avestan') was evidently a seasonal one, but it is not clear how it was kept in harmony with the seasons. There are currently three main calendars in use: Fasli, Shahanshahi, and Qadimi:
FASLI ('seasonal'): A religious calendar which is kept in harmony with the seasons by intercalculating one day every four years, patterned after the Gregorian calendar. Naw Ruz (New Year's Day) is fixed on March 21.
SHAHANSHAHI (or Shenshai): The calendar of many Parsee Zoroastrians, including some of the more influential Dasturs (High Priests). It is based on a religious calendar which was theoretically synchronized with the seasons by intercalculating a month every 120 years, but the intercalculation was not consistently followed. Naw Ruz was observed on August 23, 1995. A recent proposal would reform the Shahanshahi calendar by bringing it back into harmony through the intercalculation of whole months.
QADIMI ('ancient') : In 1746 a group of priests and laymen in Surat adopted the Irani calendar on the assumption that it represented an older tradition. The Qadimi calendar is one month ahead of the Shahanshahi.