Zoroastrianism was founded in the 6th century before Christ by the Persian prophet Zoroaster; at the time of Buddha.
    It was the official religion of the Persian Empire until it was conquered by Alexander the Great in 330 after Christ... if the battles at Marathon and Salamis would have been won by the Persians, today we would have probably in the Western civilization Zoroastrianism, instead of Christianity... finally the Muslims defeated them in the 7th century AC.
    The Zoroastrians were scattered, and today there are left 115,000 around Bombay, in India, and 7,000 in the United States.

    In India the Zoroastrians are called the Parsis (Persians), they acquired vast fortunes, in the cotton and steel industries, they have the highest literacy rate in India, and their cultural and economic importance is far out of proportion to their small numbers.

    Zoroastrianism is "monotheistic", but with a "dualistic" System: Only one loving God, Ahura Mazda, the creator, who had 2 sons: One choose "Good", the other choose "Evil" (Angra Mainya, Ahriman), the destructive principle of greed, anger, and darkness (the Satan of Christianity)... there is a constant fight between Good and Evil, but at the end, in the year 2,600 AC Good will triumph, there will be a "Final Judgment", the dead will be resurrected, and there will be a Paradise on earth.

Scriptures: Their Bible is the  Zend Avesta  Avesta-Zoroastran Archives

The priesthood is hereditary, and the "sacred fire" is used in purification rituals in "fire temples", as the Fire-Altar shown... eventually, the priests practiced magic, divination astrology...

It had influence on Christianity and Islam, with the monotheistic view, Heaven, Hell, Judgment...

The "dead"... "vultures":
    The Sun and earth are sacred, so much that the dead can not be buried on earth... the Parsis in Bombay, place the dead on the top of 3 "towers of silence" set in gardens on a hill, where vultures consume the flesh, because death is caused by the devil and the corpse is evil... Jainism have the same thoughts and practices on the dead.