Chapter I
What it means
For Zoroastrians fire is the most perfect image of God: it gives light and warmth, cannot be made impure and rises always upward. Prayers are said facing a fire or another source of light, such as the sun.
Every temple fire is tended by priests who wear a mask over their mouths, so their breath does not pollute it, and feed it with sandalwood. The fire is a living presence, honoured like a king.
Chapter II
Where it comes from
Fire was sacred among the ancient Iranian peoples before Zoroaster, and the prophet made it the focus of worship of the one Wise Lord. Fire temples with permanently burning fires appear in the late Achaemenid or Parthian period and were very numerous under the Sasanian kings (224–651 CE).
When Zoroastrians fled to India in the 8th–10th centuries, they founded a sacred fire at Sanjan. That fire, now kept at Udvada in Gujarat, is believed to have burned for over a thousand years.
Chapter III
Where you see it today
Fire temples, called agiary or dar-e mehr, serve Zoroastrian communities in India, Iran and the diaspora. There are nine Atash Bahram, fires of the highest grade: eight in India and one in Iran, at Yazd. At home, many Zoroastrians keep an oil lamp burning.