Heavyweight unification series Heavyweight unification series The heavyweight unification series, also known as the Heavyweight World Series, was a sequence of professional boxing matches held in 1986 and 1987 to crown an undisputed champion of the heavyweight class. The series was produced by HBO Sports and promoted by Don King. It ended with Mike Tyson as undisputed champion, holding the championship belts of the International Boxing Federation, World Boxing Association, and World Boxing Council. Prior to the series, the last undisputed heavyweight champion had been Leon Spinks, who won the championship in his 1978 victory over Muhammad Ali. Spinks had been stripped of
International Boxing Union (since 1996) World Super Middleweight title fights of Scott "The Sandman" Pemberton and Omar Sheika that became ESPN2's "Fight of the Year" in 2003 and 2004. On 7 April 2012, 7-time multiple weight class World Champion James Toney captured the vacant IBU World Heavyweight championship with a TKO over World Heavyweight Bare Knuckle Championship Holder Bobby Gunn. International Boxing Union (since 1996) The International Boxing Union (IBU) is a professional boxing sanctioning body founded in Atlanta, Georgia, United States, in 1996. It is unrelated to the International Boxing Union, based in Europe, which operated until the Second World War. Although the IBU