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 boxing championship records and statistics of boxers claiming to be legitimate champions. On August 23, 1962, the NBA officially became the World Boxing Association and moved their headquarters to Panama City, Panama. A year later NYSAC along with European Boxing Union and BBBofC supported creation of the World Boxing Council. In April 1983, members of United States Boxing Association along with Robert W. Lee (a former WBA vice-president) voted to expand the organisation and form the USBA-International. The organization later changed the name to International Boxing Federation. The inaugural IBF Heavyweight Champion was Larry Holmes, who relinquished the WBC title to accept IBF's recognition, thus