Muhammad Ali posted his first Twitter message on Tuesday, 50 years to the day after he stopped Sonny Liston at Miami Beach to win his first heavyweight boxing title.

"I shook up the world against Liston, now 50 years later I'm taking it to Twitter," Ali wrote with the hashtag AliTweet showing it was from the Ali himelf and a link to a photo of him screaming with his arms upraised seconds after the historic triumph.

Ali, who was then named Cassius Clay, stopped Liston in the seventh round to claim the world heavyweight crown at age 22, launching a career that would see him become a global sports icon.

Ali's official website prepared to launch a Twitter quote of the day, collecting the wit and poetry from Ali's amazing career, including such lines as "float like a butterfly, sting like a bee."

The Muhammad Ali Center, a museum in his hometown of Louisville, Kentucky, posted the Twitter message, "Today marks 50 yrs since Ali became hvywt champ! HE SHOOK UP THE WORLD!" with a link to YouTube video highlights of the Liston fight.

The Center also rewteeted a photo image from the fight with Clay landing a left to the face of a bloodied Liston.

The day after beating Liston, Clay changed his name and the legend of Ali began. It included refusing to be drafted into the US Army that was sending soldiers to fight in Vietnam, being stripped of his titles and banned from boxing for 3 1/2 years until a US Supreme Court ruling upheld his conscientious objector status to the Vietnam War.

Ali finished 56-5 with 37 knockouts and won the heavyweight crown three times in all, notably in the Rumble in the Jungle in Zaire in 1974 with an eighth-round knockout of George Foreman and in 1978, when he lost the crown to Leon Spinks in February by split decision but reclaimed it with a unanimous 15-round decision seven months later.

Ali retired after that, coming back to lose two later bouts before finally calling it quits for good in 1981.

It was in 1984 when Ali announed that he had been diagnosed with Parkinson's Disease, which silenced the snappy banter that had been his youthful trademark but did not dim his status in sports or humanitarian efforts.

In 1990, Ali visited Iraq and negotiated the release of 14 US hostages from Saddam Hussein.

At the 1996 Centennial Olympics in Atlanta, it was Ali -- a gold medal winner from the 1960 Rome Olympics -- who lit the torch at the opening ceremony.

In 2005, Ali received the Presidential Medal of Freedom, the highest US civilian honor.

One of the most iconic photos in sport, Ali standing above a flattened Liston, came not from their first fight but from a rematch in Lewiston, Maine, in May of 1965, which Ali won by knockout in the first round.