As we celebrate the Vernal Equinox, the Islamic Solar New Year, commonly known in the West as the Persian New Year, controversies abound as to its origin and re-identification.
The year was 1073 CE when Sultan Jallaluddin Malikshah I commissioned a counsel of astronomers, headed by the renowned Omar Khayyam of Nishapur, in the observatory of Isfahan to solve the problem of the ebb and flow of seasonal drift in the Islamic lunar calendar.
This counsel of the brightest Muslim scientists studied for six years the principles of the ancient Indian Surya Siddhanta, the Chinese-Uighur calendar systems, and the many mathematically calculated solar calendars at the time and integrated them with the astronomical calculations that the Muslim scientists had perfected and thus created the world's most scientific calendar with an accuracy rating that surpassed every calendar known to humanity at the time. The year was computed from the northern vernal equinox, and each month was determined by the transit of the sun into the corresponding zodiac region, i.e. the position of the earth in relation to the sun in its solar orbit. "Omar Khayyam compiled many astronomical tables and performed a reformation of the calendar which was more accurate than the Julian and came close to the Gregorian (sic). An amazing feat was his calculation of the year to be 365.24219858156 days long, which is accurate to the 6th decimal place!"
The solar calendar was adopted on 15 March 1079 as the Jallali Calendar in recognition of the royal patronage of Sultan Jalaluddin Malikshah I and was given its Islamic character as it was retroactively reckoned from the year of Prophet Muhammad's migration to Medina, making 622 CE as the year zero and its first year as the year 457 AH. Conventions were established to use the designations HS for Hijri Shamsi, 'solar hijri' for the use in government administration and HQ for Hijri Qamari, 'lunar hijri,' to be used primarily for rites and rituals in religious holidays. For centuries the Jalali Calendar was used alongside the Islamic Lunar Calendar.
The decline in the use of the solar hijri came with the rise to power of the Safavids in Persia in the 16th century. Perhaps with a hint from Christian Europe, the Safavids 'ideologized' Persia's political culture, emphasizing a 'nation state' distinct from the rest of the Muslim world: They adopted the (Twelver) Shi'ism as their state religion and force-converted some 65% of their Sunni subjects. They patronized Persian as their official language and Persianized the entire population linguistically, and they renamed the Jallali calendar as 'Persian.'
Furthermore, they claimed as 'Persian' every significant personality or entity from the vast pool of common Islamic heritage that could be linked to 16th century Persia through language, geography, history, ethnicity, etc. This polarization brought them into a devastating rivalry with the Ottomans for centuries. The rift continues to fuel the Shi'i-Sunni schism and political rivalry to this day.
The Safavid chauvinism alienated neighboring Muslim states and institutions who soon relinquished the use of Persian language and along with it the use of the Jallali Calendar and began to use the lunar calendar for both government and religious affairs.
Fast forward to the 20th century when the rising trend of European nationalism reached the Northern Tier countries among the Ottomans, the Persians, and the Afghans. In the wake of the Constitutionalist Reforms in Persia, the parliament officially claimed the Jallali Calendar as 'Persian' in 1911.
Afghanistan officially re-adopted the Jallali Calendar in 1922 retaining the original Arabic names for the months as devised by Khayyam and established their equivalents in Pashto years later. In an attempt to even out the variations in month lengths and simplify the astronomic computations, the calendar was further modified in Persia in 1925 and in Afghanistan in 1957.
In 1925, Officer Reza Khan, the first ethnic Persian ruler of Persia in nearly a millennium, claimed Sassanid connection and called himself 'the Pahlavi.' With the persuasion of the Nazis who needed to root their Aryan claim in a nation state, the Pahlavi court tapped onto referential points in the common literary history of the region and laid claim to the Aryan heritage in 1935 and formally renamed Persia as Iran--a derivative of Aryan.
With the European inspired nationalism, it was a foregone conclusion that the revival of Zoroastrian traits and traditions would come at the expense of the country's Islamic heritage. To that end the Pahlavi court eliminated the Arabic names of the astronomical zodiac signs that Khayyam had assigned to the Jallali Calendar and replaced them with corresponding Avestan or Middle Persian names whose consonantal clusters had to be modified to accommodate the modern Persian phonetic system. The final push of this 'cultural chauvinism came during the 2500th anniversary of the founding of the Persian monarchy in October 1971 when Muhammad Reza Pahlavi attempted to abandon the Islamic character of the hijri calendar and reckon it with the establishment of the Achaemenids.
Calendars are generally associated with religious traditions and cultural communities and not with nation states. Therefore, the term 'Persian Calendar', in contradistinction to the renamed Jallali calendar, implies a calendar of the Persian religious community, the Parsis or Zoroastrians and not necessarily the Persian state. This is particularly so when that state had already abandoned the name 'Persia' in favor of 'Iran.' Not to mention the fact that the word 'Iran' too has cultural and historical implications far beyond the geographic boundaries of modern day Republic of Iran.
Be that as it may, the renaming of the Jallali Shamsi Calendar as 'Persian calendar' eclipses the real Persian Calendar(s) of the Parsis, the Zoroastrian religious communities in the world. The rightfully named Persian Calendar of the Zoroastrians was drawn on the Sumerian, Babylonian, and Egyptian calendars. It was largely based on Zoroastrian cosmology that dates to the later Achaemenid period (650 to 330 BCE), the Parthian calendar dated of 248 BCE, and the Sassanid calendar modified in 224 CE. The calendar was certainly not astronomically calculated as was the Jallali Calendar, instead months of uneven length accommodated seasonal change in the solar cycle. It had many intercalary days to be added every now and then and each of the 30 days of each 12 month--as well as the days of the week--had a name of religious significance. There were an additional 5 days (gathas) added to the 12th month to make a 365-day year.
The real Persian or Khorshidi Calendars are still used by the Zoroastrian communities in India, Persia, and around the world and have gone through several seasonal adjustments and alignments from as far back as 1006 CE to as recently as 1990. The modern manifestation of these ancient traditions appears as three distinct calendars: Yazdegirdi (Shahenshahi), Qadimi, and Fasli.
In this cultural tug-of-war and one-upmanship these politically redefined identities have created chaos and confusion whose inevitable prevalence persistently stirs up political sensitivities. The more the Iranians claim the traits of the common culture as 'Persian/Iranian', the more their neighboring states abandon them.
Many Muslims, primarily Arab states who were deprived of the use of one of their greatest scientific achievements, the Jallali Calendar, began using the Christian Gregorian calendar instead. The Turks, for instance, have renamed the Gregorian months in Arabic, Aramaic, Latin, and Turkish.
Some of the most well-known cultural traditions of the Jallali Solar Calendar like the solstices and equinoxes that were celebrated by the people of Central Asia are now viewed with suspicion and considered non-Islamic, Zoroastrian, heretic, or blasphemous. A case in point is the tragic attack on Afghan New Year festivities in 2013.
The Islamic solar calendar had a great start, but unfortunately it got caught up in the entanglement of the post 16th century malaise of the Muslim world. Ever since the commonalities of cultural heritage are confined to nationalistic claims and padding of political identities, i.e. molding political psyches in the illusion of past glory without building the present for a sustainable future. This has led to the fragmentation of the Muslim world that haunts the region to this day.