In 1967, heavyweight boxing champion Muhammad Ali had refused induction into the U.S. Army as a conscientious objector, claiming it was against the teachings of Islam. His stance had led to his expulsion from professional boxing, as well as the legitimate threat of prison time on felony charges.

While Ali fought a legal battle to retain his freedom, "Smokin'" Joe Frazier emerged as the consensus heavyweight champion of the world. Like Ali, he had been an Olympic gold medalist, and while he lacked the graceful moves and magnetism of his predecessor, his hammer of a left hook left little doubt about his worthiness to hold the title.

In 1970, the window back to boxing finally cracked open for Ali when he was granted a license to fight in Georgia. Following his wins over top contenders Jerry Quarry and Oscar Bonavena, the public received the fight they wanted with the announcement that Ali and Frazier, both undefeated, would square off for the heavyweight crown.

Ali’s insults generated publicity and infuriated Frazier

Ali immediately set about fanning the flames of anticipation for the "Fight of the Century" by badmouthing his opponent. As described in Ali: A Life, he called Frazier an Uncle Tom, saying he was too dumb and ugly to be the champ.

To Frazier, who had publicly supported Ali and even lent him money in his exile, the insults amounted to a betrayal of their friendship. While Ali was correct in calculating that his diatribes would generate publicity, they had the side effect of infuriating his opponent past the point of redemption.

Meanwhile, the country's clashing cultural forces closed ranks around their chosen side: Ali was the draft dodger, the figurehead of the anti-war movement and the disruption of traditional values. And Frazier, who grew up in a poor sharecropping family in the South, ironically became a symbol of the establishment – the "white man's champion," as Ali derisively put it.

Joe Frazier vs. Muhammad Ali at Madison Square Garden
Muhammad Ali throws a punch at Joe Frazier at their 1971 match in New York City.
Photo: Dan Farrell/NY Daily News Archive via Getty Images

A thrilling bout culminated with Frazier’s dramatic knockdown of Ali

On March 8, 1971, the atmosphere was electric at New York City's Madison Square Garden. Men in full-length white sable coats and leopard capes mingled with A-list celebrities like Barbra Streisand, Dustin Hoffman and Sammy Davis Jr.; Burt Lancaster was there to provide commentary for closed-circuit TV, while Frank Sinatra was perched ringside with his camera, ready to shoot photos for LIFE magazine.

The crowd of 20,455 erupted when Ali emerged, wearing red trunks with white stripes and shoes tasseled with bow-tied laces. Seconds later, another roar greeted the appearance of Smokin' Joe, clad in green and gold brocade trunks.

The fight began at a frantic pace, with both men bobbing and throwing wild punches. Ever the showman, Ali shook his head whenever Frazier caught him with a solid body blow, dismissing the idea he was hurt.

However, it soon became apparent that the showman could no longer dance around the ring as he'd done in his youth. He took to trading blows with Frazier which, while a seemingly sound strategy for a bigger man with a longer reach, also left him open to the devastating firepower of his opponent.

Gaining steam, Frazier bloodied Ali's nose in the fourth round and began hammering him on the ropes, the ex-champ's prediction of a sixth-round knockout eroding with every punishing blow he absorbed.

In the ninth, Ali seemingly regained control by battering Frazier with a flurry of combinations. The tide turned again in the 11th round when Frazier hit home with a seismic left hook. Ali wobbled around the ring in dramatic fashion, seemingly playing possum, though he was legitimately hurt. He wasn't finished yet, however, digging deep to thrill the crowd with an inspiring show in round 14.

Heading into the 15th and final round, Frazier was ahead on all three judges' cards, though Ali's recent revival suggested that the fight could still go either way with one brutal knockdown.

At 2:34, it came – as Ali loaded to deliver an uppercut, he was caught flush in the face by a hook that could have toppled the entire building. Down he went, for just the third time in his career to date.

Amazingly, Ali popped back up as if he had merely stumbled, but his fate was sealed. After the final bell, Frazier was announced the winner by unanimous decision.

The match bolstered the reputations of both men

One of the few athletic events to live up to the enormous hype that preceded it, the Fight of the Century was reportedly watched by 300 million people around the world and generated an estimated $20-plus million in revenue, with each participant receiving a record $2.5 million purse.

For Frazier, the match ensured his permanent place in boxing history, the first to professionally defeat Ali and the one who would push the Greatest to the limit across the two later bouts of their storied trilogy.

And for Ali, it marked a turning point in his remarkable career, the one from which he proved he could overcome diminishing physical ability to rise as the heavyweight titleholder once again, completing his turn from a controversial figure of the tumultuous '60s into the ultimate champion of the people.

Muhammad Ali