PIR-E-HERISHT, Iran -- Dressed in white to symbolize purity, the priest carried a torch down the steps of the temple and set fire to a pile of wood to end the celebration of one of the world's oldest religious rites.

Sadeh, or the feast of creation of fire, has been observed by Zoroastrians since ancient times, when their religion was the state belief in the powerful Persian empire. This year, it took on new vigor in Iran thanks to a growing enthusiasm among the now-minority religion's young members.

While most Zoroastrians gathered at temples in their hometowns to mark the festival, some 2,000 heeded a campaign led by young believers to travel to Iran's central mountains to mark Sadeh at the Pir-e-Herisht temple, which is considered the cradle of the religion.

"Sadeh is the celebration of the foundation of ancient Iranian civilization," priest Goshtasb Belivani told his audience in modern Farsi before reciting verses from the Zoroastrian holy book, Avesta, in the language of ancient Persia.

100,000 believers

Sadeh was the national festival in ancient Persia, but Zoroastrianism lost dominance after Muslim Arabs invaded in the 7th century. Today, most of Iran's 70 million people are Muslim and the government is led by religious scholars who preach a strict version of Islam.

Some 100,000 Zoroastrians are part of Iran's small non-Muslim population, which also includes about 150,000 Christians and 25,000 Jews.

The minorities are largely allowed to practice their faiths. For instance, while the Islamic leadership bans mixed dancing, Zoroastrian men and women are permitted to dance together and play music as part of their worship in special places like temples or covered buildings.

Zoroastrians are few in today's world. The followers in Iran make up more than half the estimated 200,000 Zoroastrians around the globe.

The central theme of Zoroastrianism is the struggle between the good, or Ahura Mazda, and the evil, Ahriman, a belief that is thought to have influenced later religions from Judaism to Islam.

The religion's principal tenet is written on the main gates of all Zoroastrian temples: "Good Thoughts, Good Words, Good Deeds."

To Zoroastrians, fire represents life and the inherent nature of Ahura Mazda -- total goodness. However, they are not fire worshippers. "We worship one God," priest Belivani said in an interview.

Many records destroyed

Zoroastrian researcher Shahriyar Hirbod said many records were destroyed during the invasions by Alexander the Great and later the Arabs, so much is unknown about the origins of the religion. Even the place of Zoroaster's death is not certain, although tradition puts it in northwestern Iran.

For centuries, Zoroastrianism was the main religion of what is now Iran and the basis of the culture.

Although Islam has been dominant for centuries in Iran, some Zoroastrian rituals have survived as national holidays.

Iranians celebrate Nowruz, or the New Year, in March. They light bonfires, set off firecrackers and dance in the streets. At the winter solstice, Iranians buy fruit, nuts and other goodies to mark the feast of Yalda, an ancient tradition when families get together and stay up late.