Muhammad Ali had it all.
"The Greatest" had charisma and a sharp sense of humor. He was good-looking. He emerged in volatile times that lent urgency to his political and moral views. He brought astounding physical gifts into the ring, most significantly his speed.
And, not to be overlooked, he was fortunate to fight in an era loaded with compelling rivals.
Given his personality and talents, Ali surely would have succeeded in any era. However, a long list of highly respected foils such as Sonny Liston, Joe Frazier and George Foreman allowed him the opportunity to prove how great he truly was.
Many call Ali's time -- particularly the second part of his career -- "The Golden Era" of heavyweights.
"I've always maintained that Ali fought more big, talented, tough heavyweights than [Jack] Dempsey, [Joe] Louis and [Rocky] Marciano combined," said television boxing analyst Larry Merchant.
"He fought Frazier three times, [Ken] Norton three times, Liston twice, [Floyd] Patterson twice, [Jerry] Quarry twice, Foreman. Nobody else has ever gone through a list of guys like that."
Patterson was champion when Ali turned pro after winning the light heavyweight gold medal in the 1960 Olympics in Rome.
However, Liston, who KO'd an overmatched Patterson to win the championship in 1962 and then did it again the following year, became Ali's first significant foil.
At the time, Liston -- big, strong and mean -- seemed unbeatable. He had the left jab from hell, plenty behind it and the mentality of a killer.
Today, some look back and wonder whether Liston was as good as the hype that surrounded him at the time he met Ali. Many, including former Ring editor Nigel Collins, suggest Liston might have been older than he claimed and past his prime.
Some believe Liston was born in 1927 -- not the generally accepted 1932. He would have been 36 for the first Ali fight.
"Sonny's age was a big mystery," Collins said. "I suspect he was quite a bit older than the official biography would have him. ... The Boxing Register has him born in 1932. That may be correct, but there is a question mark involved.
"I think he was past his prime."
If you believe his official date of birth, Liston was only 31 and couldn't have been too far beyond his peak. His double demolition of the limited, but solid, Patterson proved that.
And even if you don't, it's hard to argue with his record: He was 35-1 (with 25 knockouts) and on a roll before he met Ali. He had stopped 13 of his previous 14 opponents, including some of the best fighters of the era.
One thing is certain: Few gave Ali -- Cassius Clay at the time -- much of a chance when the fighters met for the first time in 1964.
When a beaten, frustrated Liston refused to get off his stool for the start of the seventh round, claiming an injured shoulder, Ali had done exactly what he boasted repeatedly he would do: beat the unbeatable.
He then stopped Liston again the following year in the first round, the product of the "phantom punch" that some believe demonstrated Liston took a dive.
Regardless, Ali was taken seriously after that.
"Liston was considered a fearsome force," Merchant said. "He reminded some people of a bigger Joe Louis. No one thought he'd be exposed by Ali as a bully.
"... [Ali] showed a lot of skeptics how good he was."
Ali's era must be divided into two parts: before and after his three-year exile for refusing induction into the armed forces.
In Part I, the world saw the lean, blazing-quick Ali burnish his reputation and skills in a relatively deep pool of heavyweight talent. Some of those whom Ali faced in those days would dominate today, many experts assert.
Among those fighters: Henry Cooper, Patterson, Cleveland Williams, Ernie Terrell and Zora Foley -- all tough, well-schooled veterans with impressive records.
They were among the best of a solid era, one in which many of the nation's best big athletes still went into boxing rather than the safer environs of football and basketball.
"It wasn't a great era, but a good era," said historian Bert Sugar, referring to the first part of Ali's career. "And remember: Almost everyone was black. Blacks had come to the fore in great numbers by that time.
"They made the pool larger, more talented."
Collins also believes Part I was a good, though not great era, which might have benefited Ali.
Perhaps it was a perfect group of solid, but limited, opponents who allowed the young Cassius Clay-turned-Muhammad Ali to mature as a fighter and remain undefeated.
"You can pick apart the record of any fighter," Collins said. "It's also true, though, that timing is everything. Ali met a lot of those guys at the right time."
Ali spent most of 1967 through 1970 fighting not in the ring but in the courts, trying to win acceptance as a conscientious objector and remain out of prison.
Meanwhile, Joe Frazier, the Olympic heavyweight gold medalist in 1964, had climbed to the top of a heavyweight world that was beginning to spawn a litany of outstanding contenders in what would become that "Golden Era."
To climb to the top, Frazier -- a short, whirling-dervish of a fighter with a deadly left hook -- had to beat such talented foes as Oscar Bonavena, Eddie Machen, George Chuvalo, Buster Mathis, Quarry and Jimmy Ellis. And he did, winning the belt stripped from Ali when he was banned in 1967.
When Frazier fought the former champ for the title in 1971 (their first meeting), he was 26-0 and Ali 31-0, two of the greatest heavyweights ever -- one with a fearsome punch, the other with unrivaled charisma and both in or near their primes.
It's no wonder "The Fight," as it was called then, whipped even casual boxing fans into a frenzy.
Ali, perhaps rusty from his layoff, lost the first meeting by a unanimous decision but won the second two-thirds of perhaps the sport's greatest trilogy.
And that was only part of Ali's amazing résumé.
In the decade that comprised Part II of his career, he met a dizzying array of talented heavyweights whose names conjure memories of great fight after great fight -- most on network television.
Quarry. Bonavena. Ellis. Buster Mathis. Patterson. Bob Foster. Norton. Ron Lyle. Earnie Shavers. Foreman. Larry Holmes. All fighting at the same time.
"Ali, Foreman, Norton, Frazier -- you can keep going," said publicist Bill Caplan, a member of the World Boxing Hall of Fame who has been in the business a half-century.
"You can name 10 guys who'd probably beat the top heavyweights of today.
"There were great heavyweights. And then there were a lot of really good ones, like Lyle, Shavers and Quarry. That definitely was the golden age of heavyweights."
Ali's career came full circle when he met George Foreman, another scowling bear of a man who consciously patterned his demeanor after Sonny Liston's.
As in the first Liston fight, Ali was given little chance against the Herculean world champion when the two met in 1974 in Zaire.
Foreman was 40-0 with 37 knockouts, including frightening second-round KOs of Frazier (to win the title) and Norton. Perhaps no heavyweight had enjoyed such a dominating, fear-inspiring stretch of victories.
However, a foe who seemed to be superhuman instead became Ali's greatest opportunity to stake his claim as the greatest heavyweight ever.
Ali used his "rope-a-dope" strategy of laying against the ropes and allowing Foreman to wear himself out, after which Ali knocked him out in the eighth round to shock the world, as he had done against Liston 10 years earlier.
Ali would go on to beat Lyle, Frazier (in the "Thrilla in Manila"), Norton (in their third and final meeting) and Shavers before his skills began to diminish significantly, as his loss to Leon Spinks and then Holmes made clear.
Interestingly, as Ali faded, so did the division. When Holmes took over as the best heavyweight in the world, he suddenly found himself with precious few worthy opponents in what would become a relative dark age among heavyweights.
Indeed, by 1981, when Ali fought for the last time, he had taken the "Golden Era" of heavyweights with him into retirement -- but not before he took advantage of the opportunity to create a larger-than-life niche in boxing lore.
"In retrospect, he was such a unique fighter, a unique individual," Collins said. "He would have been champion and an extremely famous person no matter what era he fought in.
"... And, yes, without question, he was fortunate that there were a lot of good fighters around for him to prove himself."
Michael Rosenthal covers boxing for the San Diego Union-Tribune.