Muhammad Ali was a boxer.
The Fight of the Century ( also known as The Fight ) is the title boxing writers and historians have given to the boxing match between WBC/WBA heavyweight champion Joe Frazier ( 26 -- 0 , 23 KOs ) and Ring magazine/lineal heavyweight champion The Cyber Boxing Zone ( CBZ ) website maintains an official list of lineal champions in professional boxing , with input from boxing historian Tracy Callis of the International Boxing Research Organization ( IBRO ) . Muhammad Ali ( [ ɑːˈliː ] born Cassius Marcellus Clay Jr. ; January 17 , 1942 -- June 3 , 2016 ) was an American professional boxer and activist . He was known for trash talking , and often freestyled with rhyme schemes and spoken word poetry , both for his trash talking in boxing and as political poetry for his activism , anticipating elements of rap and hip hop music . In professional boxing , the undisputed champion of a weight class is a boxer who is recognized as the world champion at that class by each boxing organization .