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
Boxing in the 1930s were crowned before Joe Louis began his legendary run as Heavyweight champion in 1937. He retired in 1949, still holding the title of World Heavyweight Champion. Boxing began expanding into Latin America in the 1930s: Sixto Escobar became the first world champion from Puerto Rico by defeating "Baby Casanova", who had also been crowned at the start of the decade. "Baby Arizmendi" conquered the first world title for Mexico in 1934. For his part, "Kid Chocolate" became the first world champion from Cuba. Three world champions won world titles in three different divisions, a feat no single fighter had accomplished