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
World Heavyweight Wrestling Championship (original version) while Joe Stecher is the youngest champion, winning at the age of 22 years, 103 days. The final reign was disputed between Ed Lewis and Edouard Carpentier and the latter was in his first and therefore only reign. All matches were held at house shows. Various promotions have been home to world heavyweight championships with origins that can also be traced back to the World Heavyweight Wrestling Championship. The National Wrestling Alliance World Heavyweight Championship assumed the original world championship's position as the preeminent wrestling championship, and claimed its lineage. Most of the following championships, all based in North America,