As the boxing world mourns the loss of the greatest champ who ever lived, we reveal the highest-earning fighters of all time, from Victorian bare-knuckle pugilist John L. Sullivan to the present day's stars. All historical financial figures are adjusted for inflation.

Iron-chinned Rocky Marciano earned around $1.7 million (£1.2m) during his professional career ($15 million/£10.3m in today's money). The legendary Italian-American boxer won all of his 49 fights, defending the world heavyweight title six times in the early 50s.

The US Olympian and former WBC lightweight champion may have lost his title to Manny Pacquiao, but David Díaz didn't do too badly at all during his 15-year professional career, amassing a fortune of $16 million (£11m).

Arturo 'Thunder' Gatti was admired for his courage and fearsome left hook. His death in 2009 under suspicious circumstances shocked the boxing world. Winning 40 out a total of 49 fights, the much-respected champ notched up $16 million (£11m) during his pro career.

The longest-reigning super-middleweight world champion in history, Welsh-Italian fighter Joe Calzaghe retained the title for an impressive 10 years, defending it 22 times – no wonder he earned so much money.

Hard as nails, John L. Sullivan aka the Boston Strong Boy was the last heavyweight champion of bare-knuckle boxing under the London Prize Ring Rules. Upon his retirement in 1892, the Irish-American pugilist had earned $1 million ($25 million / £17m when adjusted for inflation).

The flame-haired Mexican fighter is currently ranked as the world's best boxer, pound for pound, and the number one middleweight. Out of a total of 49 fights, Álvarez has won 47, netting him a fortune of $27 million (£19m).

British boxer David Haye is a former world champion in two weight classes, having enjoyed a highly successful amateur career before he went pro and cashed in. 'The Hayemaker' has made a cool £29 million (£20m) during his career.

Fellow Brit Amir Khan has also raked it in during his professional career – he currently holds the WBC Silver welterweight title and has won 31 out of a total 39 fights, giving him a personal fortune of $30 million (£20.6m).

Panamanian boxing legend Roberto Durán was nicknamed 'Hands of Stone' for good reason, winning four world titles during his 30-year career. Renowned for his OTT generosity and spendthrift ways, Durán earned $30 million (£20.6m) but has splurged away $20 million (£13.8m) of his fortune.

Like Roberto Durán, Australian rugby league player turned world-famous boxer Anthony Mundine has given away a huge chunk of his total career earnings of $30 million (£20.6m), mainly to family and friends.

Four-time super-middleweight world champion Carl Froch made a tidy sum during his stellar 14-year professional career. Bolstered by his earnings as a Sky TV pundit, the British former champ has taken home $30 million (£20.6m).

Known for his legendary showmanship and flashy southpaw style, British boxing star 'Prince' Naseem lost only one of his 37 fights during a career that netted him an estimated $33 million (£22.7m).

Considered by many as one of the greatest boxers of his generation, Miguel Cotto has snagged world titles in four different weight classes. To date, the Puerto Rican champ has earned $34 million (£23.4m).

'Sugar' Shane Mosley has won world titles in three different weight classes and was named the best fighter in the world, pound for pound from 2000 to 2001. With two comebacks under his belt, the American boxer has made a total of $35 million (£24m) over his long career.

The former middleweight and super-middleweight world champion, flamboyant British boxer Chris Eubank frittered away the vast majority of his $35 million (£24m) career earnings, forcing him to declare bankruptcy in 2005.

The former holder of several prestigious world titles, British boxing star Ricky 'The Hitman' Hatton triumphed in 45 out of the 48 matches that spanned his professional career, so it's not hard to work out why he has earned so much.

Now a light heavyweight boxer, Bernard Hopkins held the world middleweight title from 1994 until 2005. Dubbed 'The Executioner', the American fighter has raked in $40 million (£27.5m) over his extra-long career.

Roy Jones Jr. began his career as a light middleweight and went on to win a heavyweight title, the only boxer in history who has achieved this remarkable feat. Needless to say, his skill and versatility have made him mega-rich.

'Marvelous' Marvin Hagler was the undisputed middleweight world champion for a good part of the 80s, winning 62 out of a total of 67 fights during his fighting career, and netting him a substantial fortune.

Considered one of the greatest heavyweights of all time, iconic 20th century boxer Joe Louis pulled in around $4.6 million ($48 million /£33m in today's money) during his professional career, but was broke for much of his post-ring life due to bad spending habits and huge charity donations.

Former world heavyweight champion and Olympic gold medallist George Foreman made a very respectable $50 million (£34m) during his boxing career but he actually owes the bulk of his $250 million (£172m) fortune to his wildly successful grill empire.

While Muhammed Ali is no doubt the greatest boxer who ever lived, the king of heavyweight champs isn't the highest earner of all time. Ali is estimated to have earned between $40 million (£27.5m) and $82 million (£56.2m) during his peerless professional career.

Boasting a PhD in sports science, brainy Ukrainian fighter turned Politician Vitali Klitschko has been equally smart with his money, earning – and holding onto – a whopping $65 million (£44.6m) during his professional boxing career.

Puerto Rican boxing legend Félix 'Tito' Trinidad notched up 45 wins during his career, amassing $85 million (£58m) in the process. Sadly a government bond crash wiped out most of his fortune.

The Canadian-born British former boxing ace is the last undisputed world heavyweight champion and an Olympic gold medalist. Beating every opponent he faced in professional competition, Lewis cashed in big time, making $130 million (£89m) during his career.

The highest paid boxer of the 80s, Sugar Ray Leonard was the first fighter to make more than $100 million (£68.7m) in purses, winning world titles in five different weight classes over his ultra-lucrative professional career.

Mexican-American 'Golden Boy' Oscar De La Hoya defeated 20 world champions during his 16-year professional career, generating over $700 million (£481m) in pay-per-view income and a huge fortune for himself.

The four-time world heavyweight champion who famously had part of his ear bitten off by Mike Tyson also managed to lose most of his $250 million (£172m) fortune, declaring himself bankrupt in 2012.

Like his contemporary Evander Holyfield, 'Iron' Mike Tyson famously blew most of his boxing earnings on everything from flashy cars and jewelry to exotic Siberian Tigers. Needless to say, he went bankrupt in 2003 with debts of £23 million (£15.8m).

The rags to riches Filipino champ turned politician managed to amass $500 million (£344m) during his professional boxing career, in which he became the first and only boxer to win world titles in eight different weight classes.

Widely regarded as the greatest boxer of his generation, Floyd Mayweather Jr. has earned a staggering $700 million (£481m) during his illustrious 19-year career, making him the richest boxer of all time, and then some.