The road to hell — and heaven — was paved by Zarathushtra, an ancient Iranian priest who preached a novel theology: that people who choose to do right are rewarded in an afterlife, and people who choose to do wrong will be punished.

The religion that bears his name — Zoroastrianism — influenced Judaism, Christianity and Islam, says Martin Schwartz, professor of Iranian studies at the University of California at Berkeley. Schwartz will be in Salt Lake City next week to deliver the 16th annual Reza Ali Khazeni Memorial Lecture in Iranian Studies at the University of Utah.

Zarathushtra (known in Greek as Zoroaster) preached in verse, and it is his poetry — but not much else about the poet priest himself — that has survived. The Iranian culture of 1000 B.C. was preliterate, so Zarathushtra composed and presented the poems orally, and they were transmitted orally for generations, from priest to priest. In those days, Schwartz says, revelations about divinities took place in poetry rather than prose sermons.

Zarathushtra's poems, he says, are full of "wondrous textures." And it is "precisely because of the many layers of complexity — the material encoded into the words through double meanings and manipulations of sound — that his poetry seemed inspired," he believes.

Schwartz will speak about "The World of Zarathushtra" at 6:30 p.m. Friday in the Fine Arts Museum Auditorium on the University of Utah campus. He also will present a more academic lecture, "The Sound of Vision: The Poetics and Theology of Zarathushtra's Gathas," at 4:30 p.m. Thursday in Room 255 of Orson Spencer Hall.

"For sure, most people — John and Jane Q. Public — don't have a clue about Zarathushtra," says Schwartz. "I don't even know what Zoroastrians know about him. He's sort of mythologized," based on semi-mythical stories about him composed after his death, Schwartz says.

As for the man himself, he was a priest who lived sometime between 1200 B.C. and 900 B.C., he probably preached a religion "with original elements that he claims to have derived from visions and revelations," and he mentions in his poetry that he obtained a large number of influential patrons, Schwartz says.

A few scholars have raised doubts that Zarathushtra actually existed, and have posited that his poems were written by more than one person, perhaps by committee, perhaps over a period of time. But Schwartz isn't one of the doubters. "There's less evidence for Moses than for Zarathushtra," he says.

The religion that grew out of his preachings about right and wrong, heaven and hell and a savior who would come to save the world was at one time practiced by an estimated 50 million people. But most Zoroastrians in the Near East submitted to conversion under the pressure of the Arab conquest of Iran after the rise of Islam in the seventh century, and the religion today is estimated to have fewer than 200,000 followers.