From humble roots in the segregated South, they grew up to become the disparate voices of Black America in the 1960s, that dark and defining era when America was ripped asunder by two wars — one in the jungles of Vietnam, the other in the streets and backroads of Alabama, Mississippi, and other places where racism flourished.

When Cassius M. Clay Jr. was born in Louisville on Jan. 17, 1942, Martin Luther King Jr. was in Atlanta, Ga., only two days removed from his 13th birthday. Clay was the son of a sign painter; King’s father a Baptist minister. Almost from the cradle, they both had tongues of silver.

King followed his father into the pulpit of the Ebenezer Baptist Church, but he quickly became more than a minister. He became the leader, the symbol, of the civil-rights movement that exposed the deep-seated segregation that had been a way of life in Dixie long after President Abraham Lincoln signed the Emancipation Proclamation.

Clay, too, became a preacher of sorts. Using the boxing rings of the world as his bully pulpit, he adopted the Muslim religion and changed his name to Muhammad Ali. When he refused induction into the U.S. Army in 1967 on the grounds that he was a Muslim minister, he sparked as much hatred in White America as he did idolatry among the poor, underprivileged, and disenfranchised around the world.

Yesterday was the 79th anniversary of Dr. King’s birth, and tomorrow will be Ali’s 66th birthday. King was killed by an assassin’s bullet in 1968, when he was only 39. Ali still is active as he can be, given the Parkinson’s disease that has left him quivering and virtually speechless.

As orators, they were decidedly different.

His grammar impeccable and his timing perfect, Dr. King spoke in a rich voice that resonated with passion and emotion. He was the epitome of dignity, modesty, and reason — a practitioner of non-violence. On the other hand, Ali delivered long harangues that were tinged with hatred, braggadocio, and militancy. Sometimes he spoke in rhymes. He never advoicated violence outright, but he associated with those who did, including the charismatic Malcolm X, who was killed after softening his anti-white stance.

In his most famous speech, Dr. King said, “I have a dream.”

In Ali’s most famous statement, he said, “I ain’t got nothin’ against them Cong.”

The voice of reason (Dr. King) and the voice of revolution (Ali) burst into the national consciousness more or less together in 1963.

That spring, speaking to hundreds of thousands gathered in Washington between the Washington Monument and the Lincoln Memorial, Dr. King delivered what came to be known as his signature speech.

“…I have a dream that one day on the red hills of Georgia, the sons of former slaves the sons of former slave owners will be able to sit down at the table of brotherhood. I have a dream that my four little children will one day live in a nation where they will not be judged by the color of their skin, but by the content of their character…”

To this day, that speech’s power and eloquence — its truth, mostly — reverberates through a nation that still is struggling to make Dr. King’s dream real.

That same year, Clay emerged as the No. 1 challenger to heavyweight boxing champion Sonny Liston. They met on Feb. 25, 1964, in Miami Beach, and, as Clay did, indeed, “shock the world,” as he repeatedly shouted, by take the championship belt away from the glowering ex-convict when Liston didn’t answer the bell for the eighth round.

“I am the greatest!” a manic Clay shouted to budding media star Howard Cosell (”Cassius, give me back the microphone,” Cosell muttered in the ring) and anybody else who would listen.

In the late summer or early fall of 1964, the FBI secretly taped a telephone conversation between King and Clay after the champ’s first trip to Africa. As reported by Tom Hauser in his Ali biography, here was the summary found in the FBI files:

“MLK spoke to Cassius, they exchanged greetings. MLK wished him well on his recent marriage. C. invited MLK to be his guest at his next championship fight, MLK said he would like to attend, C. said he is keeping up with MLK, that MLK is his brother, and he’s with him 100 per cent but can’t take any chances, and that MLK should take care of himself, that MLK is known worldwide and should watch out for them whites, said people in Nigeria, Egypt, and Ghana asked about MLK.”

Although they were equally villified by white supremacists and glorified in Black America, King and Clay remained separated by religious, political, and philosophical differences. However, on April 27, 1967, after Clay had refused to step forward and join the U.S. Army at the Houston, Tx., draft board, King stood in the pulpit of the Ebenezer Baptist Church and praised the brash young champ for his conscientious objection to the war in Vietnam.

A month later, they met in Clay’s hometown of Louisville, where King and the Southern Christian Leadership Coalition were leading open-housing marches in the weeks before the Kentucky Derby. Here’s how Taylor Branch recounted it in Bearing The Cross, his King biography:

“On March 29, King arrived in Louisville for SCLC’s board meeting in a serious, but good-natured frame of mind. He met privately with boxing champion Muhammad Ali, a Louisville native.”

According to writer Dave Kindred, author of a book about the Ali-Cosell relationship, there’s no sign anywhere that Dr. King ever considered Ali to be a minister or social activist.

“King thought the Nation of Islam, particularly in the person of Malcolm X, was a threat to his own movement in that it refused to accept non-violence as a strategy, preached and practiced segregation and hate, and left itself open to being charged with advocating violence,” Kindred said.

When Dr. King was assassinated by a sniper (James Early Ray was convicted of the act) in Memphis on April 3, 1968, Ali was struggling to make a living while his appeal of the draft board’s ruling worked its way through the judicial system. Finally, the U.S. Supreme Court exonerated him in 1970, but boxing refused to restore the championships the sport had unjustly taken from him.

Quickly returning to the ring, Ali got a title shot against Joe Frazier in 1971, but suffered the first loss of his pro career. Frazier then lost the title to George Foreman, and Ali beat Foreman in Zaire, Africa, in 1973 to get it back for the second time. He kept it until being upset by Leon Spinks in 1978, but took it back from Spinks later that same year, thus becoming the first man to win the world heavyweight championship three times.

After his final bout — a loss to Trevor Berbick in the Bahamas in 1981 — Ali retired. It wasn’t long before he began showing the effects of Parkinson’s Disease, which reduced his once-strident voice to a whisper and deprived him of the unique physicall skills that separated him from all heavyweight champions, before and since.

Aging gracefully, Ali reinvented himself to the point that he inherited Dr. King’s mantel as a man of peace. Only a whispering, struggling shadow of the youthful Clay, Ali devoted himself to humanitarian and charitable causes. He traveled the nation and the world to spread the teachings of Allah, and even became a goodwill ambassador for a couple of U.S. Presidents.

His last hurrah on the international stage came at the 1992 Olympic Games in Dr. King’s hometown, Atlanta, when he shocked and delighted the world one more time by materializing, almost mystically, from the warm Georgia night to labor up a long flight of stadium stairs, the cheers of the world’s athletes lifting him, to light the Olympic torch.

On Nov. 19, 2005, as a result of the “new” Ali’s humanitarian efforts, the Muhammad Ali Museum and Learning Center was dedicated on Main Street in downtown Louisville. Former President Bill Clinton attended the ceremony, as did actors Brad Pitt and Angelina Jolie.

The passing of time has softened the memories of the 1960s, and smoothed over the hard feelings that much of White America harbored for both Dr. King and Ali. At the time, many citizens perceived them as threats and trouble-makers, even enemies of the American way. Even today, in some isolated pockets of racism, those feelings have not changed. Some will take their hatred of Dr. King and Ali to their graves, never believing that the ends justified their very different means.

As Ali observes his 66th birthday two days after the nation paused to observe the anniversary of Dr. King’s birth, he may read something spiritual. But chances are, it will be the teachings of Allah, not Dr. King.

Editor’s note: The orginal version of this piece appeared in the Kentucky Commerce Cabinet New Digest in January, 2005.