Editing Iranian calendars (section)

===Zoroastrian calendar===
{{Main|Zoroastrian calendar}}
{{See also|Cappadocian calendar}}
The first calendars based on [[Zoroastrian calendar|Zoroastrian]] cosmology appeared in the later Achaemenid period (650 to 330 BC). They evolved over the centuries, but month names changed little until now.

The unified [[Achaemenid Empire]] required a distinctive Iranian calendar, and one was devised in [[Egyptian calendar|Egyptian tradition]], with 12 months of 30 days, each dedicated to a [[yazata]] (Eyzad), and four divisions resembling the Semitic week. Four days per month were dedicated to [[Ahura Mazda]] and seven were named after the six [[Amesha Spenta]]s. Thirteen days were named after Fire, Water, Sun, Moon, [[Tishtrya|Tiri]] and Geush Urvan (the soul of all animals), Mithra, [[Sraosha]] (Soroush, yazata of prayer), [[Rashnu]] (the Judge), [[Fravashi]], [[Verethragna|Bahram]] (yazata of victory), Raman (Ramesh meaning peace), and [[Vayu-Vata|Vata]], the divinity of the wind. Three were dedicated to the female divinities, [[Daena]] (yazata of religion and personified conscious), [[Ashi]] (yazata of fortune) and [[Arshtat]] (justice). The remaining four were dedicated to [[Asman]] (lord of sky or Heaven), [[Zam]] (earth), Manthra Spenta (the Bounteous Sacred Word) and Anaghra Raocha (the 'Endless Light' of paradise).

The month names and their modern versions are given in the following table.

{| class="wikitable"
|-
| rowspan = "2" | Order
| style="text-align:center;"| '''[[Avestan language|Avestan]] name of the Yazata (in the [[genitive case|genitive]])'''
| style="text-align:center;"| '''Approximate meaning of the name'''
| style="text-align:center;"| '''[[Zoroastrian Middle Persian|Pahlavi Middle Persian]]'''
| colspan="3" style="text-align:center;"| '''Modern Iranian Persian'''
|- style="text-align:center;"
|| '''''Romanized'''''
|| '''''English'''''
|| '''''Romanized'''''
|| '''''Native Script'''''
|| '''''Romanized'''''
|-
| style="text-align:center;"| 1
| style="text-align:center;"| [[Fravashi|Fravašinąm]]
| style="text-align:center;"| (Guardian spirits, souls of the righteous)
| style="text-align:center;"| Frawardīn
| style="text-align:center;"| {{lang|fa|فروردین}}
| style="text-align:center;"| Farvardīn
|-
| style="text-align:center;"| 2
| style="text-align:center;"| [[Asha Vahishta|Ašahe Vahištahe]]
| style="text-align:center;"| "Best Truth" / "Best Righteousness"
| style="text-align:center;"| Ardwahišt
| style="text-align:center;"| {{lang|fa|اُردیبهشت}}
| style="text-align:center;"| Ordībehešt
|-
| style="text-align:center;"| 3
| style="text-align:center;"| [[Haurvatat|Haurvatātō]]
| style="text-align:center;"| "Wholeness" / "Perfection"
| style="text-align:center;"| Khordād
| style="text-align:center;"| {{lang|fa|خرداد}}
| style="text-align:center;"| Khordād
|-
| style="text-align:center;"| 4
| style="text-align:center;"| [[Tishtrya|Tištryehe]]
| style="text-align:center;"| "Sirius"
| style="text-align:center;"| Tīr
| style="text-align:center;"| {{lang|fa|تیر}}
| style="text-align:center;"| Tīr
|-
| style="text-align:center;"| 5
| style="text-align:center;"| [[Ameretat|Amərətātō]]
| style="text-align:center;"| "Immortality"
| style="text-align:center;"| Amurdād
| style="text-align:center;"| {{lang|fa|اَمرداد}}
| style="text-align:center;"| Amordād
|-
| style="text-align:center;"| 6
| style="text-align:center;"| [[Kshathra Vairya|Xšaθrahe Vairyehe]]
| style="text-align:center;"| "Desirable Dominion"
| style="text-align:center;"| Shahrewar
| style="text-align:center;"| {{lang|fa|شهریور}}
| style="text-align:center;"| Shahrīvar
|-
| style="text-align:center;"| 7
| style="text-align:center;"| [[Mithra|Miθrahe]]
| style="text-align:center;"| "Covenant"
| style="text-align:center;"| Mihr
| style="text-align:center;"| {{lang|fa|مهر}}
| style="text-align:center;"| Mehr
|-
| style="text-align:center;"| 8
| style="text-align:center;"| [[Aban|Apąm]]
| style="text-align:center;"| "Waters"
| style="text-align:center;"| Ābān
| style="text-align:center;"| {{lang|fa|آبان}}
| style="text-align:center;"| Ābān
|-
| style="text-align:center;"| 9
| style="text-align:center;"| [[Atar|Āθrō]]
| style="text-align:center;"| "Fire"
| style="text-align:center;"| Ādur
| style="text-align:center;"| {{lang|fa|آذر}}
| style="text-align:center;"| Āzar
|-
| style="text-align:center;"| 10
| style="text-align:center;"| [[Ahura Mazda|Daθušō]]
| style="text-align:center;"| "The Creator" (i.e. Ahura Mazda)
| style="text-align:center;"| Day
| style="text-align:center;"| {{lang|fa|دی}}
| style="text-align:center;"| Dey
|-
| style="text-align:center;"| 11
| style="text-align:center;"| [[Vohu Manah|Vaŋhə̄uš Manaŋhō]]
| style="text-align:center;"| "Good Spirit"
| style="text-align:center;"| Wahman
| style="text-align:center;"| {{lang|fa|بهمن}}
| style="text-align:center;"| Bahman
|-
| style="text-align:center;"| 12
| style="text-align:center;"| [[Spenta Armaiti|Spəntayā̊ Ārmatōiš]]
| style="text-align:center;"| "Holy Devotion"
| style="text-align:center;"| Spandarmad
| style="text-align:center;"| {{lang|fa|اسفند}}
| style="text-align:center;"| Esfand
|}

The calendar had a significant impact on religious observance. It fixed the pantheon of major divinities, and also ensured that their names were uttered often, since at every Zoroastrian act of worship the yazatas of both day and month were invoked. It also clarified the pattern of festivities; for example, Mitrakanna or [[Mehregan]] was celebrated on Mithra day of Mithra month, and the Tiri festival (Tiragan) was celebrated on Tiri day of the Tiri month.

In 538 BC [[Cyrus the Great]] (uncertain if he was a Zoroastrian) conquered Babylon and the Babylonian luni-solar calendar came into use for civil purposes.  [[Cambyses II|Cambyses]] conquered Egypt in 525 BC.  He was accompanied by [[Darius the Great|Darius]], a Zoroastrian who became ruler of the Persian empire in 517 BC. The Zoroastrians adopted the wandering Egyptian solar calendar of twelve months of thirty days plus five [[Intercalation (timekeeping)#Solar calendars|epagomenal days]]. As their year began in the spring (with the festival of ''norouz'') the ''epagomenai'' were placed just before ''norouz''.

In Egypt the star Sirius had significance since every 1460 years (the [[Sothic cycle]]) its [[heliacal rising]] (just before sunrise) marked the Egyptian new year and the inundation of the Nile.   In Persia also the star had significance, since its heliacal rising there also coincided with the coming of the rain.   The fourth Persian month was ''Tishtrya'' (Sirius, rain star).   The vernal equinox at Greenwich fell on the first day of the first month from 487 to 483 BC (inclusive).   Adopting S H Taqizadeh's date of 28 March 487 BC for the reform<ref>Taqizadeh S H:  ''Old Iranian Calendars'', Royal Asiatic Society (1938).</ref> the calendar for that year is as follows:

{|class="wikitable" style="float:centre"
|+ * denotes 1 Epagomene
!Egyptian month||First day||Persian month||First day
|-
|4||23 March||1||23*–28 March
|-
|5||22 April||2||27 April
|-
|6||22 May||3||27 May
|-
|7||21 June||4||26 June
|-
|8||21 July||5||26 July
|-
|9||20 August||6||25 August
|-
|10||19 September||7||24 September
|-
|11||19 October||8||24 October
|-
|12||18 November||9||23 November
|-
|1||18*–23 December||10||23 December
|-
|2||22 January||11||22 January
|-
|3||21 February||12||21 February
|}

The fourth month includes 20 July, the date of the heliacal rising of Sirius.   In the first year the people carried on using the old calendar, anticipating festival dates by five days.   As each day is named after a god, it is important to observe the celebrations on the right day.   Thus the ''fravasis'' festival, which in the old calendar was kept between sunset on 30 Spandarmad and sunrise on 1 Frawardin, was now observed throughout the ''epagomenai''.   In the second year of the reform, the old 30 Spandarmad was the new 25 Spandarmad, so from then on the festival covered eleven days, up to the new 1 Frawardin.   Five days was considered enough for other festivals, however.

In all the lands where the Persian calendar was used the ''epagomenai'' were placed at the end of the year.   To offset the difference between the agricultural year and the calendar year (the tax-gathering season began after the harvest) the start of the ''araji'' (land-tax) year was delayed by one month every 120 years.   A Roman historian, Quintus Curtius Rufus, describing a ceremony in 333 BC, writes:

<blockquote>The magi were followed by three hundred and sixty-five young men clad in purple robes, equal in number to the days of a whole year; for the Persians also divided the year into that number of days.<ref>Curtius, iii, 10.</ref></blockquote>

After the conquests by [[Alexander III of Macedon|Alexander the Great]] and his death, the Persian territories fell to one of his generals, [[Seleucus I Nicator|Seleucus]] (312 BC), starting the [[Seleucid]] dynasty of Iran. Based on the Greek tradition, Seleucids introduced the practice of dating by era rather than by the reign of individual kings. Their era became known as that of Alexander, or later the [[Seleucid era]]. Since the new rulers were not Zoroastrians, Zoroastrian priests lost their function at the royal courts, and so resented the Seleucids.   Although they began dating by eras, they established their own era of Zoroaster.

That was the first serious attempt to determine the dates associated with the prophet Zoroaster's life. Priests had no Zoroastrian historical sources, and so turned to Babylonian archives famous in the ancient world. From these they learned that a great event in Persian history took place 228 years before the era of Alexander. In fact, this was the conquest of [[Babylon]] by Cyrus the Great in 539 BC. But the priests misinterpreted this date to be the time the "true faith" was revealed to their prophet, and since [[Avestan]] literature indicates that revelation happened when Zoroaster was 30 years old, 568 BC was taken as his year of birth. The date entered written records as the beginning of the era of Zoroaster, and indeed, the [[Achaemenid Empire|Persian Empire]]. This incorrect date is still mentioned in many current encyclopedias as Zoroaster's birth date.