CNN – By the time the first bell rang and Joe Frazier came bobbing towards him, Muhammad Ali was already four years into a fight that helped define him as one of the 20th century's most influential figures.
Under the lights at Madison Square Garden on March 8, 1971, Ali was once again fighting for the world title and, for many fans, boxing's true heavyweight champion had finally returned from exile.
Banished as one of the most electrifying and polarising figures of the late 1960s, Ali had become the face of protest, and the man to unite the anti-war movement with the ongoing struggle for civil rights and racial equality.
For the "Fight of the Century," everyone who was anyone sat ringside.
There was Frank Sinatra, hanging on the ring apron as a photographer for Life magazine; and writer Norman Mailer putting words to the action.
Singers and actors — Barbra Streisand, Dustin Hoffman and Sammy Davis Jr — sprinkled stardust over the proceedings.
"I remember the announcer saying, 'I'm not going to make any introductions,' everybody's here!" recalls Mike Silver, boxing historian and author of "The Arc of Boxing" and "The Night the Referee Hit Back," who was in attendance at the fight 50 years ago.
"This huge 20,000 plus fraternity of people were just generating this electricity and anticipation," Silver tells CNN Sport.
"Three hundred million people throughout the world saw this fight on television, in Africa and Asia, Europe, Japan, China … When that first bell rang, a roar went up, a roar!"
Cassius Clay — the young man from Kentucky who would become Ali — won gold at the 1960 Rome Olympics, before climbing to the top of the professional game with footwork and wit that dazzled, infuriated and ultimately changed heavyweight boxing.
Frazier — an Olympic gold medalist at the 1964 Tokyo Olympics — had grown up on a sharecropper's farm in South Carolina.
"Smokin" Joe moved to Philadelphia, where he worked in a meat locker beating sides of beef with his fists — the inspiration for a storyline in the film Rocky.
After Clay beat champion Sonny Liston, he changed his name and spent three years ruling the heavyweight division. But, after refusing induction into the military, Ali was stripped of the title in 1967.
In Ali's absence, Frazier won the world heavyweight crown, defeating Jimmy Ellis in 1970. Frazier also lent Ali money while he was excluded from the sport and campaigned both publicly and privately for the former champion to be cleared to box.
'Denied simple human rights'
"A heavyweight championship was more important sometimes than a presidential election," says Silver.
"Certain fights, Johnson vs. Jeffries, Dempsey vs. Tunney, Ali vs. Frazier … It was more in the public consciousness.
"Silver describes the fight between Ali and Frazier — two undefeated heavyweight champions coming together — as unprecedented in the history of boxing due to the bout's wider significance.
"This wasn't just a prize fight," reflects Silver. "This had other dimensions to it: the dimensions of race, politics, the Vietnam War.
"Ever since Ali won the world title, he had courted controversy.
As the newly-crowned heavyweight champion he had thrown off his "slave name" and while congress passed the Civil Rights Act of 1964, Ali joined a Black separatist group that rejected racial integration.
In 1966, US armed forces entered their fifth year in Vietnam and the government expanded the military draft.
Ali requested to be excluded, as a conscientious objector, but was denied. Staying true to his convictions at his scheduled induction in 1967, he was arrested, found guilty at the subsequent trial, and sentenced to five years in prison and handed a $10,000 fine.
"Why should they ask me to put on a uniform and go 10,000 miles from home and drop bombs and bullets on brown people in Vietnam, while so-called Negro people in Louisville are treated like dogs and denied simple human rights?" Ali had asked.
So the heavyweight title was taken from him, as was his passport, and boxing commissions refused to license him to fight.
On the floor of the US Congress in 1967, Republican Robert Michael said: "He may look upon himself as 'the greatest,' but I am sure history will look upon him as 'the least' of all men who have held the once honorable title of heavyweight champion of the world."
Dr. Amira Rose Davis, professor of history and African American studies at Penn State University, says "a lot of leaders were terrified" of Ali.
"He was vilified for his opposition to the war, vilified for being outspoken, and vilified for connections with the Nation of Islam," adds Davis.
In August 1970, Ali was permitted a license to fight in Atlanta, and the former champion was back in boxing, winning bouts against Jerry Quarry and Oscar Bonavena. Later in 1971 — after the "Fight of the Century" — the US Supreme Court overturned Ali's conviction in an 8-0 ruling.
"Ali made himself into somebody who's very significant in terms of his ability to command an audience," says Davis.
"To have the cameras on him and to use those cameras to speak hard truths about what it's like to be a Black man in the US, to talk about foreign policy, particularly the war.
"Because of his status, he also gets the opportunity to go on these late-night talk shows and to have cameras in his face and he never shies away from talking about civil rights or talking about police brutality.
"He's important because he allows us to see so many fractures and divisions. There are so many people that saw him as a man of the people, that saw him as a mouthpiece for their struggles."
'Cannon fodder for the state'
As opposition to the war grew, Ali's draft case also helped reveal the disproportionate number of African Americans dying in Vietnam.
"He opposed the war," says Davis. "But he also gave new arguments for its opposition. He connected the opposition to the war within a framework about the treatment of Black Americans. He talked about not being cannon fodder for the state and not being a pawn.
"Frazier rose to prominence in the years Ali was absent from the ring, but he also found himself becoming a foil to the more controversial Ali.
"He [Frazier] comes to symbolize a kind of more complacent, conservative America," says Davis. "And the fight then takes on this larger meaning about the very fabric of the country and what side is going to be dominant in the ring.
"Ali was happy to feed that narrative, ratcheting up the tension with claims Frazier represented the establishment. "He painted it as if you're supporting Frazier, you're against equality, you're against justice," says Davis.
"He was basically saying I'm fighting for the people in the ghetto. I'm fighting for the Black community. I'm the man of the people, and Frazier is the man of the people who are trying to oppress you — continuing to push this framework of seeing it as a fight about pro-war conservativism versus anti-war civil rights.
"Silver draws parallels between 1971 and the present day.
"We're now living in America through quite a disruptive and divided time. I can only compare it to that time. I didn't think I would see such a divided country again.
"It's astounding the divisiveness you see in America now, and if there's any comparison to it, it is the Vietnam War era in this country and then before that the Civil War."
While boxing, and the world heavyweight championship, have diminished in influence over the past 50 years, other sports and athletes have risen to prominence. Notably NBA superstar LeBron James, who has become a leading voice against racial injustice and police brutality, and is talked about "in the same genre" as Ali.
Civil rights activist Harry Edwards places James at the forefront of the fourth and fifth "waves of athletic activism" in a continuum that includes Wyomia Tyus, Tommie Smith and Ali.
Edwards says that fourth wave came in 2012 when James and his Miami Heat teammates wore clothing to honor Trayvon Martin, an unarmed high school student shot and killed by a neighborhood watch coordinator in Florida, while the fifth came in 2020.
"I understand that for athletes you're going to take some hits from fans," four-time Olympic gold medalist Michael Johnson told CNN Sport. "You're going to have some people saying, 'I don't want politics and social issues in my sport."
However, Johnson is conscious to highlight what happened to Colin Kaepernick, the former San Francisco 49ers quarterback who started kneeling during the National Anthem to protest police brutality in 2016 and has been unsigned to a team since 2017.
It was two years in February that Kaepernick and former teammate Eric Reid settled their collusion grievance cases against the NFL.
"You only have to look back as far as Colin Kaepernick and what was done to him and what happened to his career to understand why athletes might be apprehensive," said Johnson.
'How did he bounce up after that shot?'
"The Fight of the Century" lived up to the hype.
"It was the most intense heavyweight fight I have ever seen," says Silver.
"Ali did get under Frazier's skin," he adds. "By the time the fight took place, they genuinely didn't like each other. They were fighting with an intensity I've rarely seen.
"And Frazier fought a fight that was almost hard to believe for a heavyweight, to fight that kind of pace for 15 rounds.
"I think you would have had to have killed Frazier to keep him from winning that fight.
"In the 15th and final round, Frazier floored Ali with a left hook, and it looked as if the contest was over, before, to the amazement of the crowd, he got straight back up.
"For many years, I thought when Ali was hit with that left hook in the 15th round. How did he bounce up after that shot?" says Silver.
"Ali sensed it. He saw it coming, but he couldn't get out of the way in time. If that was Ali of four years earlier before the layoff, he would have moved his head away.
"What's interesting is that we found out in that fight what we didn't know before: Because Ali rarely was hit solidly, we found out in that fight he could take a punch.
"It was a great fight. It had drama, intensity, momentum and, of course, capped off by the climax of Ali getting dropped in the 15th round, that was the icing on the cake.
"Frazier won the bout on points, by a unanimous decision, giving Ali the first loss of his professional career.
To commemorate the former champion and his famous win 50 years ago, friends and family of Frazier will unveil a statue inside the new Joe Hand Gym in Feasterville, Pennsylvania.
Weatta Frazier Collins — one of the heavyweight boxer's 11 children — is championing her father's legacy with a scholarship fund which is awarded to vulnerable teenagers.
In January of 1973, Frazier lost the title to George Foreman, and Ali was again to shock the world, knocking Foreman out during the late-1974 "Rumble in the Jungle" fight in Kinshasa, Zaire — to reclaim the crown he had lost seven years before.
In all the reverence Ali is held in — "a Buddha-like figure" as Silver puts it — his treatment of Frazier often crossed a line, calling his rival an "Uncle Tom," a demeaning term for Black people who are viewed subservient to whites, and a "gorilla."
"I swallowed a lot of razor blades," Frazier told a HBO documentary that was aired in 2000," and sometimes they cut … inside."
In a 2001 interview with The New York Times, Ali said he had used that language as a way to promote the fight.
"In a way, Joe's right," said Ali. 'I said a lot of things in the heat of the moment that I shouldn't have said. Called him names I shouldn't have called him. I apologize for that. I'm sorry. It was all meant to promote the fight.'
'In that same New York Times interview, Frazier said he accepted Ali's apology. "We're grown guys. This has been going on too long. It's like we've been fighting the Vietnam War.''
"It's hard with Frazier," Davis explains. "He was somebody who didn't speak out a lot. He kept his head down and really focused on the sport. He was like many Black athletes of the day, who, for whatever reason, were not Ali.
"It's much more common to be a Joe Frazier and you can see this incredible way that boxing became a vehicle for upward mobility and in many ways, for me he represents a great majority of Black athletes who are just grinding.
"I think there's a way now, that we look back so positively on athletic activism that it's like why weren't you as outspoken? But the truth is Ali was an anomaly."
According to Silver, Ali's activism "started a trend."
"If you're looking at the athletes today who speak out, the forerunner of this was Muhammad Ali, and they owe him something, for good or bad," says Silver.
"You can get some sense how outraged people were because you see the reaction to Colin Kaepernick taking a knee. I mean, look at the outrage.
"Multiply that by about 10 times and you'll know the outrage that people felt when Ali refused to be drafted into the US Army.
"In the 50 years since the fight in 1971, Ali's legend has only grown.
"Muhammad Ali solidified himself as somebody who's going to think and pay attention to not only the struggles of the Black community in the US," said Davis, "but to connect the struggles of marginalised people from Vietnam to Louisville to South Africa.
"We lose sight of the stakes and what it means to give up your title at the height of your career, to stand for something that could quite literally cost you the career.
"We know, of course what happens but he had no way of knowing he could get back to the top. I think that that's really important to understand. Especially in 1971."
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