Mehregan is one of the two most ancient Iranian festivals, the other one being Norouz.
Although there are various versions and beliefs regarding the origin of Mehregan, it is believed that it was originally a feast honoring the Zoroastrian Angel Mithra.
It is also believed that the Autumn Festival was designated to farmers for celebration of harvesting their crops.
During the Persian Empire, Autumn, was also the time for collecting taxes. Visitors from different parts of the Persian Empire brought gifts for the king all contributing to a lively festival.
Mehregan is usually celebrated on the 16th of the seventh month of Persian calendar, Mehr, at the time of harvest.