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 Championship (WWE) and championships among other assets. The slew of former WCW talent joining the WWF roster began "The Invasion" which effectively phased out the WCW name. Following this, the WCW World Heavyweight Championship was unified with the WWF Championship, the WWF's world title, at Vengeance in December. At the event, the WCW World Heavyweight Championship was decommissioned with Chris Jericho becoming the final WCW World Heavyweight Champion and the subsequent Undisputed WWF Champion after defeating The Rock and Steve Austin respectively. The WWF title became the undisputed championship in professional wrestling until September 2002 with the creation of the World Heavyweight