[custom_adv] Nowruz is the persian New Year, also known as the Persian New Year,which is celebrated worldwide by various ethno-linguistic groups.Despite its persian and Zoroastrian origins, Nowruz has been celebrated by diverse communities. [custom_adv] It has been celebrated for over 3,000 years in Western Asia, Central Asia, the Caucasus, the Black Sea Basin, and the Balkans.It is a secular holiday for most celebrants that is enjoyed by people of several different faiths, but remains a holy day for Zoroastrians, Bahais, and some Muslim communities. [custom_adv] Nowruz is the day of the vernal equinox, and marks the beginning of spring in the Northern Hemisphere. It marks the first day of the first month (Farvardin) of the persian calendar. [custom_adv] It usually occurs on March 21 or the previous or following day, depending on where it is observed. The moment the Sun crosses the celestial equator and equalizes night and day is calculated exactly every year, and families gather together to observe the rituals. [custom_adv] Nowruz was the holiday of Arsacid dynastic empires who ruled homeland and the other areas ruled by the Arsacid dynasties outside of Parthia (such as the Arsacid dynasties of Armenia and Iberia). [custom_adv] There are specific references to the celebration of Nowruz during the reign of Vologases I , but these include no details. Before Sassanids established their power in Western Asia around 300 CE, Parthians celebrated Nowruz in autumn, and the first of Farvardin began at the autumn equinox. [custom_adv] During the reign of the Parthian dynasty, the spring festival was Mehrgan, a Zoroastrian and Iranian festival celebrated in honor of Mithra. [custom_adv] Extensive records on the celebration of Nowruz appear following the accession of Ardashir I, the founder of the Sasanian Empire . Under the Sassanid emperors, Nowruz was celebrated as the most important day of the year. [custom_adv] Most royal traditions of Nowruz, such as royal audiences with the public, cash gifts, and the pardoning of prisoners, were established during the Sassanid era and persisted unchanged until modern times.