Boxing’s most dogged and opinionated observers determine the top fighters by projecting their skills against those of heavier or lighter foes via subjective “pound-for-pound” lists.
There have been fighters along the way, however, who took that responsibility upon themselves.
Though it’s much more common these days with in-between weight classes and myriad sanctioning body belts, one of the measures of greatness through the years has been whether or not a fighter could translate success at one weight into more titles up or down the weight ladder.
And while it’s true that simply dominating one division and never leaving it is no vice—particularly among heavyweights—some of those viewed as the best fighters of all time at lighter weights have shown their stuff against challengers of all shapes and sizes.
Click through to take a look at the bodies of work of those we’ve judged to be the 10 best, in terms of the impressions left by their weight-class journeys.
The record: 66-8-5 (59 KO)
The titles: Middleweight (1891), heavyweight (1897), light heavyweight (1903)
The context: The oldest of the top-10 entries was a three-division champ when being a three-division champ was far more of an accomplishment.
In fact, the turn-of-the-century Brit was the first boxer to pull off the feat and remained the only former middleweight champ to win a heavyweight title until Roy Jones Jr. did so in 2003. Fitzsimmons was inducted into the International Boxing Hall of Fame as an old-timer in 1990. Far from a giant, he would be more suited to super middleweight or light heavyweight in modern times.
Arguello's third weight class belt came when he decisioned Scotland's Jim Watt at lightweight in 1981.
The record: 89-8 (70 KO)
The titles: Featherweight (1974), junior lightweight (1978), lightweight (1981)
The context: One of the staples of CBS boxing coverage in the early 1980s, Arguello earned more public acclaim through television appearances at lightweight—including a 14th-round TKO of then-unbeaten Ray “Boom Boom” Mancini—than he had while conquering 126 and 130 pounds.
He ultimately fell short in two bids to become the sport’s first four-time champion, losing twice to Aaron Pryor at 140. A strong technical fighter with good power, Arguello could be troubled by fleet-footed boxers in his prime but little else.
The record: 54-5-2 (38 KO)
The titles: Flyweight (1998), junior featherweight (2001), junior lightweight (2008), lightweight (2008), junior welterweight (2009), welterweight (2009), junior middleweight (2010)
The context: The Filipino was a favorite of the hardcore fans for his entertaining style in the early years before becoming an international phenomenon with an unprecedented climb up the weight-class ladder.
Though he hasn’t always fought the premier fighter in a given division to capture his belts, no one can deny his remarkable rise from flyweight dynamo to welterweight punisher. A devastating KO loss to Juan Manuel Marquez in late 2012 has raised doubts about his future career arc.
The record: 150-21-10 (101 KO)
The titles: Featherweight (1937), welterweight (1938), lightweight (1938)
The context: The first fighter to hold three weight-class titles simultaneously will remain the only one for as long as modern sanctioning bodies dictate that champions give up one belt to defend another.
Armstrong held three belts when there were only eight overall weight classes, and he narrowly missed gaining a fourth when his bout against middleweight claimant Ceferino Garcia was judged a draw in 1940. His perpetual motion style and good chin would have served him well against frustrate opponents from any era.
Even at 36, Mayweather showed little indication of decline in a May victory over Robert Guerrero.
The record: 44-0 (26 KO)
The titles: Junior lightweight (1998), lightweight (2002), junior welterweight (2005), welterweight (2006), junior middleweight (2007)
The context: The top man in most legitimate pound-for-pound debates these days, Mayweather began his career with an Olympic bronze medal in 1996 and was a professional champion at 130 pounds two years later.
He became the top man in four subsequent weight classes in a five-year stretch between 2002 and 2007 and will return to 154 pounds to meet unbeaten Saul "Canelo" Alvarez in September. His fast hands, defensive prowess and ring smarts would make him a tough out for any of history's best fighters.
The record: 103-16 (70 KO)
The titles: Lightweight (1972), welterweight (1980), junior middleweight (1983), middleweight (1989)
The context: One of the fiercest fighters at any weight, Duran was a menace at 135 pounds before skipping up to 147 to bully a then-unbeaten Ray Leonard. His career seemed doomed when he surrendered in a rematch, but he reinvented himself with a massacre of Davey Moore at 154 and went on to stun Iran Barkley at 160 six years later.
His actual boxing skill was often undervalued because of his persona, which was enough to unnerve all but the heartiest of opponents.
The record: 36-3-1 (25 KO)
The titles: Welterweight (1979), junior middleweight (1981), middleweight (1987), super middleweight (1988), light heavyweight (1988)
The context: The second greatest “Sugar Ray” of all time was a superstar before he threw a professional punch, but he quickly proved his mettle and captured his first title at age 24.
A memorable pair with Roberto Duran and a classic showdown with Thomas Hearns all occurred at 147, but Leonard cemented his legacy by returning from hiatus to shock middleweight Marvin Hagler in 1987. His belts at 168 and 175 are less legitimate given his opposition and the catchweight at which the dual-title coronation took place, but he earned every bit of his overall acclaim by performing his best against his best opposition.
Hearns settled an old score with a two-knockdown performance against Ray Leonard in 1989, though the judges ultimately scored the bout a draw.
The record: 61-5-1 (48 KO)
The titles: Welterweight (1980), junior middleweight (1982), light heavyweight (1987), middleweight (1987), super middleweight (1988), cruiserweight (1999)
The context: In a comparison based solely on a given fighter’s body of cross-divisional work, few can compare to Hearns, who was a fearsome puncher in his early days before utilizing superb boxing skills to engineer several later victories.
The 154-pound KO of Roberto Duran was as vicious as any on a big-fight level, and he outboxed Ray Leonard in their 1989 rematch at super middleweight only to be denied by the judges in a disputed draw. His range of 43 pounds between titles (welterweight and cruiserweight) is rivaled only by Pacquiao (112 to 154) among the multi-title greats.
The record: 56-8 (40 KO)
The titles: Middleweight (1993), super middleweight (1994), light heavyweight (1997), heavyweight (2003)
The context: Though he’s better known to younger fans as a declining 40-something who won’t let it go, Jones was far more than that while establishing himself as the sport’s best over a decade-plus. His one-sided defeats of champions like Bernard Hopkins, James Toney, Mike McCallum and Virgil Hill set a standard of athletic greatness.
His 2003 defeat of 226-pound heavyweight titleholder John Ruiz was his last truly spectacular moment in the ring. The victory improved him to 48-1 as a pro and made him just the second ex-middleweight champ to win a heavyweight title.
The record: 173-19-6 (108 KO)
The titles: Welterweight (1946), middleweight (1951)
The context: The measuring stick for a half-century’s worth of great fighters and the inspiration for a few that have followed him into the ring, Robinson mixed pure boxing artistry with breathtaking one-punch power. He won the welterweight crown as a 25-year-old before making the jump to middleweight and holding that division’s title on five separate occasions.
His rivalries with brawlers Jake LaMotta and Carmen Basilio are the stuff of bull vs. matador legend, and only heat prostration kept him from capturing the light heavyweight crown in 1952—when he retired on his stool after 13 rounds with Joey Maxim while far ahead on the scorecards. No less an authority than ESPN labeled him as the greatest fighter of all time in a 2007 article.