On February 25, 1964, Cassius Clay was crowned the heavyweight champion of the world. Twenty two year old Clay defeated Sonny Liston, who was the reigning heavyweight champion of the world at the time, in what is considered as one of the biggest upsets in the history of boxing. Liston, who was a feared boxer, had twice defeated former champion Floyd Patterson and was a favorite to win the match. However, after six rounds were complete and the bell rang for the seventh round, Sonny Liston failed to respond and Cassius Clay was declared the winner in front of a crowd of 8,300 spectators at the Convention Hall arena in Miami Beach. Later Cassius Clay, one of the greatest sports figures of the 20th century, changed his name to Muhammad Ali.