LOS ANGELES--In 1964, 22-year-old world heavyweight champ Cassius Marcellus Clay Jr. shocked the public by converting to Islam and changing his name to Muhammad Ali. Three years later he claimed conscientious objector status as "a minister of the religion of Islam" and refused induction into the U.S. Armed Forces. That decision cost Ali his title; a judge convicted and sentenced him to five years imprisonment and a $10,000 fine and subsequently revoked his passport and barred him from fighting in the United States.

Ali's conviction because of his religious stance and his life inside and outside the boxing arena is the subject of "Ali," a Columbia picture produced, co-written and directed by Michael Mann ("The Insider") and starring Will Smith as The Champ. The film opened on Christmas Day.

"Ali" is the story of a religious man whose newfound faith is put to the test and who overcomes adversity because of his piety. The movie's release amid America's war against terrorism seems untimely, yet its message of religious tolerance and nonviolence couldn't be more appropriate.

"Many people doubted that (his Islamic belief) was sincere. He made clear to everyone that his religion was a perfectly sincere faith in his worldview," said Stephen J. Rivele, who shared screenwriting credit on the movie with his writing partner Christopher Wilkinson, as well as Eric Roth and Mann.

Rivele says that Ali's conversion to Islam is probably the pivotal event in the screenplay. "It represented the kind of public declaration that athletes were not able to make in those days," he said.

"We wanted to try to portray Ali's entire life," Rivele said. "There's a whole generation out there that really doesn't know the man's life. You can't (portray Ali) without understanding the man's spiritual quest to find God."

"Ali" follows the boxer's life from 1964, when he defeated Sonny Liston for the Heavyweight Championship and adopted the Muslim faith, to his 1974 fight against George Foreman in Zaire (the famous "Rumble in the Jungle"). The movie features flashbacks to his days as a youth in Louisville, Ky., and his alignment with Elijah Muhammad under the Nation of Islam. His refusal of Uncle Sam's call to duty made front page news. "I ain't got no quarrel with them Viet Cong" he once told a reporter.

"If you look at what he sacrificed as a religious principle, it was unprecedented at his time," said Rivele, 52, who co-wrote the movie "Nixon" with Wilkinson. "He became a symbol of courage in the name of belief."

Ali did indeed take a stand against fighting in Vietnam when it was still unpopular to do so. At that time, "sports figures were supposed to be one-dimensional quasi-cartoon characters," said Thomas Hauser, author of the 1991 biography "Muhammad Ali: His Life and Times."

"I'm expected to go overseas to help free people in South Vietnam, and at the same time my people here are being brutalized and mistreated, and this is really the same thing that's happening over in Vietnam," Ali told the author.

But Ali caused a public stir when he converted to Islam. He changed his name to Muhammad, and the media refused to use it. Even sports commentator Howard Cosell, who apologized to Ali for calling him Cassius Clay at a press conference, faced condemnation for his public support of the boxer.

"It was an interesting alliance because you had a practicing Jew supporting a Muslim," Rivele noted of the Cosell-Ali relationship. In the movie, Jon Voight plays Cosell.

As a Muslim, Ali opposed integration and intermarriage, and he spoke out against the glorification of white imagery in American culture. His wit could sometimes cut across racial lines. "Angel food cake is the white cake, but the devil's food cake is chocolate," Ali was quoted in his biography. The white, blue-eyed Jesus of popular Christian paintings was especially offensive to African-Americans, he said. "Where are the colored angels?" he asked. "They must be in the kitchen preparing milk and honey."

To be sure, "Ali" shows the boxer's conflicts with women and his somewhat boisterous manner and outbursts toward his boxing opponents. But the movie's message of religious conviction in the face of adversity propels its story.

Ali fought all the way to the U.S. Supreme Court, where, in 1971, the judges unanimously overturned his conviction on the grounds of religious freedom. The victory was bittersweet for The Champ, who had sacrificed his boxing career and lost much of his fortune in order to follow what he believed was God's call. Ali eventually returned to the boxing arena.

For Rivele, the movie demonstrates how one man's belief in God can change history. His hope is that younger audience members will walk away with the movie's message of tolerance and nonviolence.

"If you truly believe in the good and what is right and you are prepared to sacrifice, you can change the way people think and you can change the way whole societies think without resorting to violence," he said.