Sure Rocky Marciano was great. He did finish 49-0. But who did he beat? LaStarza and Joe Louis?. The Heavyweight Division was so weak then. Ali beat Frazier twice, Norton twice. He handed Foreman his ass so Foreman didnt want to fight again. He beat Sonny Liston twice at the age of 22. Plus he came back after three years of not fighting because he was stripped of the right to fight. He was the youngest Heavyweight Champion at the time. He was the first to ever regain it 3 times. And he did this without his prime years. He was unable to fight from age 26 to 29. He won the Olypic Gold in 1960. He's never been beaten by a KO. He won the title a second time, SEVEN years after winning it the first time.