Muhammad Ali showed an early interest in boxing and won a gold medal in the Olympics. He went on to become the heavyweight champion, encouraging many others with his power and confidence in the ring. Although he lost his first match against Joe Frazier, Ali was able to come back and defeat Frazier in a rematch. Ali remained champion for several years until he was defeated by Trevor Berbick in 1979, after which Ali chose to retire at age 39, wanting to let other boxers have a chance to become champion.