10th Level He was active for no less than 28 years and had the most wins by KO. Although it took him 17 years to win the world title
9th Level Although he was a great unknown at the time, he won his first world title at the age of 19 by KO over Chatchai Sasakul
8th Level The 'Cincinnati Cobra' (95-25-1, 52 KO) competed with the elite from middleweight to heavyweight for the better part of a decade without a title shot
7th Level With a record of 229-11-1 (65 KO), this featherweight champion won his first 62 fights with four victories over Ring 'top 10' opponents, including his featherweight title win over Chalky Wright
6th Level Floyd won titles in five categories and we already know that he has been the boxer with the most box-office and PPV success in recent decades and perhaps in history
5th Level Griffith (85-24-2, 23 KO) was at the top of the welterweight and middleweight rankings from the early 1960s to the mid-1970s, a period in which he won five world championships against top boxers
4th Level If today Mayweather boasts a perfect record against numerous world champions, in another era, Tony Canzoneri (137-24-10, 44 KO) went on to beat the best from bantamweight to lightweight with big wins at welterweight as well.
3rd Level In his three-year post-suspension period, he continued to defeat some top-ranked fighters, going on to face 37 top 10s in his 61 fights
2nd Level The Brown Bomber reigned for a dozen years with a record 25 consecutive title defences against the best of his era. Seventeen of Louis' (66-3, 52 KO) 25 defences were against top 10 boxers
1st Level Ray Robinson (174-19-6, 109 KO) went on unbeaten streaks of 40 and then 91 fights, and a record against champions and top 10 fighters, with over 40 wins.