List of boxing quadruple champions

A quadruple champion in boxing refers to a boxer who has won world titles in four different categories of weight.

There is some dispute on which sanctioning body is considered "major" enough to award championships. The "Big 4" sanctioning bodies are always included. They are arranged in order of foundation:

The Ring, boxing's most respected magazine that was founded in 1922, has its own version of lineal championship and began awarding championship belts in 1922. The Lineal Champion is also known as the true champion of the division. The Ring Champion holds the linear reign to the throne, the man who beat the man. The Ring stopped giving belts to world champions in the 1990s but began again in 2002.

In 2002, The Ring attempted to clear up the confusion regarding world champions by creating a championship policy. It echoed many critics' arguments that the sanctioning bodies in charge of boxing championships had undermined the sport by pitting undeserving contenders against undeserving "champions", and forcing the boxing public to see mismatches for so-called "world championships". The Ring attempted to clear up the confusion regarding world champions by creating a championship policy that is "intended to reward fighters who, by satisfying rigid criteria, can justify a claim as the true and only world champion in a given weight class." The Ring claims to be more authoritative and open than the sanctioning bodies' rankings, with a page devoted to full explanations for ranking changes. A fighter pays no sanctioning fees to defend or fight for the title at stake, contrary to practices of the sanctioning bodies. Furthermore, a fighter cannot be stripped of the title unless he loses, decides to move to a different weight division, or retires.

There are currently only two ways that a boxer can win The Ring's title: defeat the reigning champion; or win a box-off between the magazine's number-one and number-two rated contenders (or, sometimes, number-one and number-three rated). A vacant Ring championship is filled when the number-one contender in a weight-division battles the number-two contender or the number-three contender (in cases where The Ring determines that the number-two and number-three contenders are close in abilities and records).

In May 2012, citing the number of vacancies in various weight classes as primary motivation, The Ring unveiled a new championship policy. Under the new policy, The Ring title can be awarded when the No. 1 and No. 2 fighters face one another or when the Nos. 1 and 2 contenders choose not to fight one another and either of them fights No. 3, No. 4 or No. 5, the winner may be awarded The Ring belt. In addition, there are now six ways for a fighter to lose his title: lose a fight in his championship weight class; move to another weight class; not schedule a fight in any weight class for 18 months; not schedule a fight in his championship weight class for 18 months, even if fighting at another weight class; not scheduling a fight with a top 5 contender in any weight class for two years; or retiring.

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