Nowruz is a Zoroastrian holiday marking the first day of spring, celebrated by persons of Persian ancestry. Families gather to observe traditional rituals when the sun crosses the equator and equalizes night and day. The official day begins when the sun leaves the zodiac of Pisces and enters the zodiac of Aries.
Nowruz is believed to have been invented by Zoroaster himself. It was also important during the Achaemenid era (548-330 BC) because kings from different Persian nations used to bring girts to the Emperor.