Muhammad Ali was a legendary boxer who is widely regarded as one of the greatest athletes of all time. He was born Cassius Marcellus Clay Jr. in 1942 and changed his name to MUHAMMAD Ali after converting to Islam in 1964. He won 56 of his 61 professional fights, including 37 knockouts, and held the world heavyweight championship title three times. Ali was also an outspoken civil rights activist and philanthropist.