Nouruz, the new year festival, is one of the most important and famous festival in Iran. It is said that Nouruz originated with Jamshid. According to Nouruz Nameh attributed to 'Omar Khaiyam, at that day he found the sun entered into the Aries, which is the sign of the equinox, then he held the festival and called the day “Nouruz”. After the model of Jamshid, Iranian kings had continued to celebrate this festival on the first day of Farvardin; it flourished specially in the Sasanian period.
In those days they adopted a 365-day calendar and used to ignore the intercalation. As a result a quarter of the day had been lost annually and the whole year had slipped steadily backward. It had distressed people, as they were obliged to pay tax at Nouruz. In the eleventh century, in order to help them, Malekshah enacted a new calender and Nouruz was fixed on 21th of March, the first of Farvardin in this calendar. Since then Iranian people has celebrated Nouruz on the vernal equinox.
In this paper I try to prove that Nouruz, held on the vernal equinox, shows three characters: spring festival, agricultural festival and ancestor festival.
