"You will call me by my new name and you will like it!"
March 6, 1964: Finding that the name "Cassius Clay" lacked "divine meaning," Elijah Muhammad, leader of the Nation of Islam, stated in a radio address that the new heavyweight champion had been given the Muslim name "Muhammad Ali." "Muhammad" was chosen to represent "one worthy of praise" and "Ali" is the name of a cousin of the prophet.
Ten days earlier, on a Tuesday night in Miami, 22-year-old Cassius Clay overcame long odds as a 7-1 underdog to dethrone then-heavyweight champ Sonny Liston. Clay's upset was complete when Liston refused to continue after the sixth round, claiming a shoulder injury. The following morning, in the glow of his victory, Clay confirmed that he had joined the Nation of Islam.
The new heavyweight champion then traveled to New York, and with Malcolm X at his side, announced that he would be known thereafter as "Cassius X." The "X" was intended as a rejection of his prior surname, which had once belonged to the family for whom his ancestors were slaves.
With Elijah Muhammad's radio address shortly thereafter, Cassius X became Muhammad Ali.