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
Heavyweight boxing championship records and statistics Heavyweight boxing championship records and statistics At the beginnings of boxing, the heavyweight division had no weight limit and the category historically has been vaguely defined. In the 19th century, for example, many heavyweight champions weighed 170 pounds (12 st 2 lb, 77 kg) or less (although others weighed 200 pounds). The first heavyweight champion under the Marquess of Queensberry rules was John L. Sullivan, known as "The Boston Strong Boy". He weighed around 200 pounds when in shape and was a bare-knuckle champion. He was defeated by Jim Corbett on September 7, 1892, in 21 rounds. In 1920, the