Sadeh meaning hundred, is a mid winter feast celebrated with grandeur and magnificence in ancient Iran. It was a festivity to honor fire and to defeat the forces of darkness, frost and cold. Two different days were observed for its veneration. One celebration marked the hundred day before the religious No Ruz on the first day of the month Farvardin (religious No Ruz is different from spring No Ruz). The other one was the hundredth day after the gahambar of Ayathrima (one of the six feasts of obligation) held to be the beginning of winter. This day coincides with 10th of Bahman in present calendar. It is not clear why there are two Sadeh Festivals and why different regions have had different dates. Many of Zoroastrian holy days were and are celebrated twice; this is caused by the calendar reform in the 3rd century AD.

From Achaemenid times the Iranian calendar had 360 days and was short of 5 days. Ardeshir the first Sassanian king reformed the calendar and 5 days were added at the end. The new calendar receded slowly against the solar year, and the holy days, which with their symbolism were closely linked with the seasons, became gradually divorced from them. The months moved and so did the holy days, to make sure festivals were observed correctly both the old and the new dates were celebrated. The festival celebrated in Yazd is according to Fasli calendar and in a few villages it is called Hiromba. While the other Zoroastrians celebrated the Sadeh in Bahman. There was confusion earlier in the century as to when it should be celebrated, but most Zoroastrians have adopted the 10th of Bahman as the main event.

In Sassanian times huge bon fires were set up. Priests led the prayers specific to fire 'Atash Niyayesh' and performed the correct rituals before it was lit at sunset. People would dance around the fires. Wine an expensive luxury would be served communally and like all other Zoroastrian religious ceremonies the occasion would end with fun, merriment and feasts. The most elaborate report of the celebration comes from the 10th century during the reign of Mardavij Zeyari, the ruler of Isfahan. From Iranian origin the Zeyar family did their best to keep the old traditions alive. Huge bon fires were made in both sides of the 'Zayandeh Rood', the main river dividing the city. The fires were contained in specially build metal holders to maintain control. Hundreds of birds were released while carrying little fireballs to light the sky. There were fireworks, clowns, dance and music with lavish feasts of roasted lamb, beef, chicken and other delicacies.

The tradition was virtually lost even amongst the Zoroastrians. In Pahlavi era it was revived and adopted as a major celebration by the whole Zoroastrian community and it is becoming known and increasingly popular with the rest of the Iranians as well. With Zoroastrians the chief preparation or Sadeh is the gathering of wood the day before the festival. Teen-age boys accompanied by a few adult males will go to local mountains in order to gather camel's thorn, a common desert shrub in Iran. For most it will be the first time they are away from their families. Wood is a scarce commodity in Iran and the occasion resembles a rite of passage, a noteworthy step for the boys on the way to manhood.

The wood gathered would be taken to the local shrine and on their return home if it is their first time there will be a celebration for the boys at home with friends and relatives. However this practice is becoming more difficult these days and attempts are made to preserve it. The work is hard, wood more scarce than ever, fewer boys are prepared to attempt it and safety is a major concern. In addition massive emigration into the cities or outside the country has significantly reduced the number of boys available for this occasion.

Traditionally young boys (before the revolution girls had started joining the boys as well, but the practice has stopped since 1979) would go door to door and ask for wood and collect whatever they could get, from a broken spade-handle to logs and broken branches. While knocking on doors they would chant simple verses like "if you give a branch, god will grant your wish, if you don't, god won't favor your wish" and similar verses. All wood collected would be taken to the local shrine. Before the sunset all would gather outside the temple to torch the wood with prayers and chants remembering the great ones of the faith and the deceased.

In ancient times the fires were always set near water and temples. The great fire originally meant (like winter fires lit at other occasions) to help revive the declining sun, and bring back the warmth and light of summer. It was also designed to drive off the demons of frost and cold, which turned water to stone, and thus could kill the roots of plants beneath the earth. For this reasons the fire was lit near and even over water and by the shrine of Mihr, who was lord both of fire and the sun. Biruni in AD 1000 has very accurately described all these reasons for Sadeh Festival.

The fire is kept burning all night. The day after, first thing in the morning, women would go to the fire and each one will carry a small portion back to their homes and new glowing fires are made from the ritually blessed fire. This is to spread the blessing of the Sadeh fire to every household in the neighborhood. Whatever that is left of the fire will be taken back to the shrine to be pilled in one container and will be kept at the temple. The festivities would normally go on for three days and the wood gathering by the boys door to door and blessing of the dead happens every night and evenings are spend eating and giving away 'khairat' (giving away as a good deed). Food prepared from slaughtered lamb and 'ash e khairat' are distributed amongst the less fortunate.

Today, Sadeh is mainly celebrated on 10th of Bahman. The fires are not lit outside and all activities take place inside the shrines. The wood gathering activities are reduced though there are efforts to preserve them. However the bulk of the Iranians are becoming more familiar with the occasion and there are gatherings and celebrations outside Iran. Fires are lit, music, dancing and merriment of all kinds will go on for the rest of the evening. The occasion for the majority of Iranians has no religious significance and no specific rituals are involved other than torching bon fires at sunset and having a merry time and therefore keeping up with the ancient traditions when merriment was venerated and practiced.