Some of these ceremonies were obligatory, such as Gahambars, the anniversary of creation, producing sky, water, earth, plants, useful beasts, and humans.
The most important are Farvardinegan (Farvardin, 19th), Tirgan (Tir, 13th), Mehrgan (Mehr, 16th) and Esfandgan (Esfand, 5th).
Faravahar (Frawahar in Pahlavi, Fravashi in Avestan language, and Fravrti in Ancient Persian) is one of the internal forces that according to Mazdayasnan beliefs (Zoroastrianism), existed before the creation of the creatures, and will go to the upper world and persist there after their extinction.
The only permitted acts are to perform religious duties and good deeds to attract the Faravashis to their residences.
In the 19th day of Farvardin month, the ceremony of Farvardinegan is held to respect these eternal beings and the souls of the deceased.
In this ceremony that is called Farvardog nowadays, celebrants visit the graves of their deceased (in Tehran, and Firouzeh castle, the Zoroastrian graveyard.
They burn agarwood and olibanum for the peace of the souls and put plants, fruits, candles and laraks on the graves.