In 1964, when Muhammad Ali announced that he believed in Islam, he shocked and enraged many Americans. His association with the Nation of Islam, a radical sect most people considered a violent cult, made him the most polarizing villain in sports. Preeminent sportswriter Jimmy Cannon accused Ali of turning boxing “into a mass instrument of hate.” The heavyweight champion, Cannon charged, was “using it as a weapon of wickedness in an attack on the spirit.”

Yet Ali refused to let Cannon or any other critic define his religion. “ ‘Black Muslims,’ ” he said, “is a press word. It’s not a legitimate name. The real name is ‘Islam.’ That means peace.” Ali insisted that Americans’ suspicions of Islam were unfounded. “Followers of Allah are the sweetest people in the world. They don’t carry knives. They don’t tote weapons. They pray five times a day. . . . All they want to do is live in peace.”

Since Ali died this past weekend, the story of his conversion has been told and retold. But one subtle point has gotten lost in the recollections: Ali used boxing as a platform to promote Islam as a peaceful religion. In defense of his faith, he became a visible symbol of resistance against Islamophobia. Before of each of his fights, he would pray in his corner with his eyes closed, head bowed and his gloves turned skyward. When he embraced his “original name,” Muhammad Ali, most Americans refused to use it. It sounded too foreign and too subversive in a country that generally distrusted Muslims of any kind. In the 1960s, his boxing matches took on a larger cultural meaning as a threat to traditional Christian values.

Ali’s understanding of the conflict between Christianity and Islam in America was shaped by his experience with racism. Sometime in 1961, when he was still known as Cassius Clay, he ventured into Temple No. 29, a vacant storefront converted into a makeshift mosque in Overtown, Miami’s segregated neighborhood. A local member in the Nation of Islam, Sam Saxon, invited him inside where he heard ministers preach about the history of the black man.

But it wasn’t necessarily what he heard that day that hooked him; it was what he saw. The painting behind the lectern was divided into two sides: One represented Christianity, the other Islam. On the left side, he saw an American flag framed by a cross and a silhouette of a black man hanging from a tree. In the corners of the American flag, painted in bold letters, were the words Christianity, slavery, suffering, and death. On the right side, the corners of a red Muslim flag included the words Islam, freedom, justice, and equality. Beneath both flags, he read the central question the ministers’ posed: “WHO WILL SURVIVE THE WAR OF ARMAGEDDON?”

Clay began questioning everything he had learned in the Baptist Church growing up in Louisville. The lessons he heard in the mosque reconfigured his view of American racism and Christianity. In his mind, it was impossible to separate race and religion in America. The ministers preached that Islam was the black man’s true religion and that 400 years earlier, white Christians kidnapped, shackled, and enslaved his ancestors. And those same white Christians continued to torture blacks and use the church to pacify them into worshiping the white man’s God — a God who had the same blond hair, pale skin, and blue eyes as the slave master.

As Clay’s relationship with the Nation of Islam deepened, he began to see himself not just as a boxer who would restore interest in a dying sport, but also as a savior graced by the power of Allah. “I am the resurrection. I am the prophet,” he declared in 1963. Listening to Elijah Muhammad and Malcolm X preach about black superiority and the power of Allah’s true believers affirmed what he had always thought about himself: that he was indeed the greatest.

Clay’s unshakeable faith in himself as a divine vessel grew out of his relationship with Malcolm. In February 1964, on the eve of his fight for the heavyweight championship against Sonny Liston, nearly everyone predicted that the first round would end with Clay on a stretcher. Clay’s hysterical performance at the weigh-in — ranting and raving, insulting Liston — convinced the attending physician that the young contender feared for his life.

But Malcolm just grinned when he was asked about Clay’s fears. The boxer possessed the kind of faith that made it impossible for him to fear anything or anyone. “I’ve never heard him mention fear,” Malcolm told the writer George Plimpton shortly after the weigh-in. “Anything you’re afraid of can whip you. Fear magnifies what you’re afraid of. One thing about our religion is that it removes fear. Christianity is based on fear.”

Before the fight, Malcolm joined Clay and his brother Rudy in the dressing room for a final prayer. They bowed east toward Mecca, praised Allah and blessed his name. Malcolm prophesied that Clay would defeat Liston because Allah would protect him. The fight, Malcolm preached, was “the truth. It’s the Cross and the Crescent fighting in the prize ring — for the first time. It’s a modern Crusades — a Christian and a Muslim facing each other with television to beam it off Telstar for the whole world to see what happens!”

Then, before Malcolm left the dressing room, he tested Clay’s faith with a question: “Do you think Allah has brought about all this intending for you to leave the ring as anything but the champion?”

Clay answered the bell, stunning the world when he defeated Liston. He interpreted his victory as a blessing from Allah. Later that night, he told columnist Jim Murray that his victory made him a true believer: “I’m the champ now and God wants me to be champ. If it wasn’t God, now who was it?”

The very next day, he announced that he was a Muslim and a loyal follower of Elijah Muhammad. Barely a week after that, he would change his name to Ali. When reporters questioned him, he defended his faith not only on religious terms, but also on political grounds: He did not want to be a Christian or integrate with whites because that would expose him to violence. Islam, he said, offered a sanctuary from racism and violence. “I want peace,” he said, “and I do not find peace in an integrated world. I don’t want to be blown up.”

Although his critics argued that the Nation of Islam’s theology was inconsistent with the Koran, Ali rejected that. “Islam is a religion and there are seven hundred and fifty million people all over the world who believe in it, and I’m one of them,” he declared.

Reporters accused him of being a “card-carrying member of the Nation of Islam,” as if joining the sect was the equivalent of enlisting in the Communist Party. Former heavyweight champion Floyd Patterson attacked Ali’s religion. The proud Catholic condemned Ali as un-American, unfit to be champion. He challenged Ali to what amounted to a holy war, announcing that he would fight him anytime, anyplace. In his self-righteousness, Patterson made himself out to be more patriotic than Ali and a better citizen. “I am an American,” he said, implying that Ali was not — not as long as he practiced Islam.

Patterson saw himself as a Christian liberator fighting a “moral crusade” against Ali.  In October 1965, he wrote an article in Sports Illustrated, promising to save the sport from the “Black Muslims’ scourge.”  But six weeks later in Las Vegas, Ali punished Patterson.  The champ glided across the ring, bobbing and weaving, taunting Patterson, “Come on, American!  Come on, white American!”

It was no contest. After 12 rounds, the referee stopped the fight. Ali could have knocked Patterson out much earlier, but he wanted him to suffer.

When Patterson assaulted Ali’s faith, the champion said that he might as well have attacked “Cairo, Egypt, the Holy City of Mecca, Pakistan, Turkey, and 300,000” Muslim Americans. Defending Islam, Ali began to see himself not just as an American but as a global citizen, a guardian of Muslims under attack. Equally important, Muslims in the United States and around the world interpreted assaults on Ali as attacks on them. In a deeper sense, the boxing career of Muhammad Ali divided America along religious lines. Muhammad Ali became for Muslims what Joe Louis was for black Americans in the 1930s — their champion.