Today in History—February 25: Muhammad Ali Becomes the Undisputed World Champ

On this day in 1964 Cassius Marcellus Clay, Jr., shocked the boxing world: The unpredictable and often showy amateur took on Sonny Liston, the reigning heavyweight champion—and won.

Then just 22, Clay was known for his lax stance, his fleet feet—and his big mouth. Clay had goaded Liston into the ring with antics that bordered on harassment, including heckling him in a Las Vegas casino, greeting his plane on the tarmac to hurl insults, and honking outside his home in the middle of the night. Clay was fined by the Miami Boxing Commission on the day of the fight for his behavior.

He entered the Miami Beach Convention Hall that day a 7-to-1 underdog. Liston was a decade older, fiercer, and widely considered unbeatable. But after six rounds, nursing a brutal cut and a shoulder injury, Liston conceded. Clay screamed at the crowd: “Eat your words!”

Two days later Clay announced that he had accepted the teachings of the Nation of Islam. The following month he changed his name to Muhammad Ali—which is probably how you know him—kicking off one of the greatest careers in prizefighting history.

A rematch with Liston followed in 1965. It lasted 2 minutes and 12 seconds before Ali knocked Liston out.

Soon after, Ali’s refusal to serve in the Vietnam War reverberated through American society. Some approved of his dissent on religious grounds, but the U.S. court system wasn’t among them: He was stripped of his titles, barred from boxing, and sentenced to five years in prison. He never served a day behind bars, but he lost prime fighting years before his conviction was overturned in 1971.

When Ali returned to the ring, he was a little older, a little slower, but still willing to take on the best. He remembered how to put on a show, giving the world matches that are now part of sports mythology, like the Rumble in the Jungle (against George Foreman in 1974) and the Thrilla in Manila (against Joe Frazier in 1975).

Ali would go on to become the first three-time world heavyweight champion. He retired in 1981 with a record of 56–5.

That same year—at age 39—he talked a man off the ledge of a nine-story building and drove him to the hospital in his limo. After his retirement, Ali became known for his outspoken convictions instead of just his combinations, taking a stand on civil rights, religious freedom, and humanitarian causes.

In 1996 at the Atlanta Olympics, Ali’s hands shook from Parkinson disease as he lit the Olympic torch. He held the flame aloft, trembling as he raised it—and the world watched and cheered, just as he always demanded of it.