Ali was stripped of the WBA title in September 1964, after agreeing to an immediate rematch with Liston, which was against the body's rules at the time.
February 6, 1967
April 28, 1967
Ali reunited the belts by beating WBA champion Ernie Terrell on February 6, 1967. He was stripped of the WBA belt on April 28, 1967 for refusing induction into the United States army, but retained recognition by the WBC until February 3, 1970.
Mike Tyson became the Undisputed Heavyweight Champion as the culmination of the heavyweight unification series, by unifying his WBA and WBC, with Tony Tucker's IBF belt. The Ring magazine later recognized him as champion on June 27, 1988.
Lennox Lewis became undisputed champion by defeating Evander Holyfield, successfully unifying his WBC belt (and the lightly regarded IBO title) with Holyfield's WBA and IBF belts. Lewis was stripped of his WBA belt due to a contract dispute regarding a clause in the 2nd Holyfield contract which stipulated he must fight the WBA number 1 contender next. The number 1 contender at that time was Henry Akinwande but he was ill so John Ruiz was later moved up to number 1. The WBA gave Lewis permission under these circumstances to fight WBC/IBF #2 ranked contender Michael Grant next as long as he agreed to fight Ruiz in the following bout. Lewis agreed but Ruiz's promoter challenged the WBA's decision in court.
Evander Holyfield became the first undisputed Cruiserweight Champion by defeating Carlos De León, to unify his WBA and IBF belts with De Leon's WBC belt. He relinquished all the belts after moving up to the Heavyweight division. The Ring Magazine stopped recognizing the weight class in 1987.
Michael Spinks unified the title by defeating Dwight Muhammad Qawi. He later was awarded the inaugural IBF title, added to his undisputed recognition. He vacated all of the belts after moving to the heavyweight division.
Whilst Dariusz Michalczewski was the Lineal/WBO champion, Roy Jones Jr. defeated Reggie Johnson for his IBF belt, successfully unifying with his WBA and WBC belts. Jones relinquished his titles after he moved to the heavyweight division.
To date, there have been no undisputed super middleweight champions. The closest the division came to having an undisputed champion was on November 3, 2007, when Joe Calzaghe defeated Mikkel Kessler to unify the WBA (Super), WBC, and WBO titles; the IBF champion at the time was Lucian Bute.
Hagler was recognized as the inaugural IBF champion, adding the belt to his undisputed status. He lost the IBF and WBA belt recognitions after deciding to fight Sugar Ray Leonard. He then lost the WBC belt to Leonard.
Bernard Hopkins became the undisputed champion after defeating Félix Trinidad in a Middleweight tournament to successfully unify the WBC WBA and IBF belts. He later added the WBO to his undisputed status after defeating Oscar De La Hoya, becoming the first man to ever hold all four titles simultaneously.
Taylor lost his IBF belt for taking a rematch against Hopkins instead of fighting the IBF #1 challenger Arthur Abraham. He officially lost his undisputed status after being stripped of his WBA belt on December 14, 2006
Winky Wright became the first undisputed champion of the light middleweight division after unifying his IBF belt with Shane Mosley's WBA and WBC belts. Wright lost the IBF belt for taking a rematch against Mosley.
Sugar Ray Leonard unified his WBC with Thomas Hearns's WBA to become the first undisputed champ in seven years. Leonard later relinquished the title after retiring from boxing because of a detached retina.
Judah lost his undisputed championship to Carlos Baldomir, but despite being recognized as the "true" welterweight champion, Baldomir did not pay the sanctioning fees for the WBA or IBF. Consequently, the WBA relinquished Judah as its champion, while the IBF continued to recognise him. Judah later lost the IBF title to Floyd Mayweather, Jr.
Tszyu became the undisputed Junior Welterweight champ after defeating Zab Judah to successfully unify his WBA and WBC belt with Judah's IBF belt. Tszyu was stripped of the WBA and WBC titles because of extended inactivity due to training injuries and lost his IBF belt to Ricky Hatton.
Crawford became the undisputed champion after defeating Julius Indongo to unify his WBC, WBO, Ring, and lineal titles with Indongo's WBA and IBF belts. He vacated the IBF title 11 days later because he did not plan to return to the ring in time to meet an IBF-imposed deadline to fight its mandatory challenger, Sergey Lipinets, and shortly thereafter vacated all of his titles and moved to the welterweight class.