Muhammad Ali is a religious man.
Muhammad Ali ( [ ɑːˈliː ] born Cassius Marcellus Clay Jr. ; January 17 , 1942 -- June 3 , 2016 ) was an American professional boxer and activist . In 1966 , two years after winning the heavyweight title , Ali further antagonized the white establishment by refusing to be drafted into the U.S. military , citing his religious beliefs and opposition to American involvement in the Vietnam War . After retiring from boxing in 1981 , Ali devoted his life to religious and charitable work .