Nowrouz (March 21) marks start of the spring season, being one of the oldest ancient Iranian festival since long ago to the extent that people in different regions in the Iranian Plato celebrate it.
Nowrouz starts with the spring season. Astrologically, vernal equinox in northern hemisphere is referred to as the moment when sun exactly crosses the celestial equator heading northward. The time (Nowrouz) in the solar Hijra calendar marks the advent of the year and the first day of Farvardin. If the year starts before noon and in the first half of overnight, the day is exactly Nowrouz and if it falls in the afternoon the following day is nowrouz.
Nowrouz has been one of the greatest Iranian celebration since ancient times. Nowrouz was founded during the reign of Jamshid, the fourth king of the Pishdadian Dynasty, and during his kingdom turned into a tradition. On manifestation of Nowrouz, the Iranian epic poet, Ferdowsi, wrote 1,000 years ago that having done state affairs, Jamshid sat on his royal throne and all the state and military signatories gathered about his throne. He referred to that day, which was the first day of the month of Farvardin and start of the year, as Nowrouz and celebrated it.
The Achaemenid kings used to go to Persepolis, which was a sacred place and exclusive to prayers. In Nowrouz, they recalled different tribes, including Medians, Elamites, Babylonias and others, wearing precious local attires, to celebrate the New Year in Apadana Palace before the king and offer to him farming and animal husbandry products as gifts.
Nowrouz was also observed during the reigns of Arcacides and Sassanids. Nowrouz lasted for several days (at least six days) during reign of Sassanids, divided into two periods of "Public and Special Nowrouz". The public Nowrouz was observed for five days (Farvardin 1-5) publicly and on the sixth of Farvardin (Khordadrouz), the Special Nowrouz was held for the royal family, distinguished guests and personalities.
In Islam, especially in Shiah tradition, Nowrouz is regarded as an auspicious day and emphasis is on its commemoration. During the Abbasid era, the Caliphs welcomed Nowrouz as an occasion to receive public presents.
Nowrouz marks the start of the New Year in countries like Iran and Afghanistan where the Solar Hijra calendar is used. In Tajikistan, Turkmenistan, Iraq, Turkey, Syria, Lebanon, the Republic of Azerbaijan, Uzbekistan, Kyrgyzstan, Kazakhstan and Pakistan, however, the Christian calendar is customary and Nowrouz is celebrated as start of the Spring season. In some of the countries Nowrouz is a holiday.
The UN General Assembly in March 2010 recognized March 21 as the International Day of Nowrouz, having Iranian origin, and put it in its calendar. The text of the UN General Assembly approval refers to Nowrouz as an event having Iranian origin and dating as back as 3,000 years. Today, more than 300 million people celebrate it. Moreover, on March 27, 2010, the first International Nowrouz Festival was held in Tehran and the city was selected as Nowrouz Commemoration Secretariat.