Cassius Clay: He would later reject his name

Indeed, for a time, he was undoubtedly the most famous man on the planet.

But now even he has been rendered virtually powerless by a disease which has robbed this most imposing and verbose of men of both physical co-ordination and speech.

And yet, even at this low ebb, the dignity of the man shines through.

Muhammad Ali was born Cassius Clay in Louisville, Kentucky, on 17 January 1942.

The son of a sign painter, he began to box at the age of twelve in a local gym.

He enjoyed a dazzling amateur career which culminated in 1960, when he won the light-heavyweight Olympic gold medal in Rome.

But back home racism touched the life of even an Olympic champion. Disgusted at being refused service at a restaurant, he was said to have thrown his gold medal into the Ohio River, though this story turned out to be a myth.

Float like a butterfly

A steady succession of professional victories, reinforced by self-advertising tactics, made him famous, if not universally popular. Clay's manner in the ring was extraordinary.

He danced around his opponents, taunting them to hit him, and his showboating and nimble feet delighted the crowd.

As one admirer said, Ali would, "float like a butterfly, sting like a bee".

Cooper floored Ali, but could not win the bout

He offered further hostages to fortune by predicting not just his opponents' defeat, but in what round he would dispose of them.

In February 1964, Cassius Clay challenged the world champion, Sonny Liston. Ali teased him as an "ugly old bear" and duly knocked him out at the end of the sixth round.

Nine successful title defences followed.

But his manner out of the ring had now become quieter, less boastful.

He joined the Black Muslim sect, which called for separate black development in contrast to the inclusive approach favoured by more mainstream civil rights leaders like Dr Martin Luther King.

Vietnam controversy

He renamed himself Muhammad Ali: Cassius Clay, he said, was his "slave name".

Then, when Ali refused to sign the oath of allegiance to join the US Army, he was stripped of his title and sentenced to five years in jail - a sentence later quashed on appeal.

Regaining the heavyweight crown at the age of 32

After three years of growing unrest in the US about the Vietnam war, Ali returned to the ring. But he had lost some speed and was beaten by Joe Frazier.

Though he gained revenge two years later, Ali's greatest moment came in October 1974 when he defeated George Foreman in Zaire in the so-called "Rumble in the Jungle". The eighth-round knockout regained the championship he had first won a decade earlier.

He was 32, and only the second man ever to win back the title.

Ali was at the height of his powers: a heavyweight with a destructive punch and the speed of a welterweight.

In Manilla, Ali met Frazier, who by now confessed to hating the champion, for the third time.

It was their hardest fight - and perhaps the best of all time - with Smokin' Joe's corner conceding victory after 14 brutal rounds.

Third title

But in February 1978, disaster struck. Ali lost his title to Leon Spinks, a man 12 years his junior.

The return fight eight months later in New Orleans, drew a world record gate, while millions watched on television.

This time Ali outclassed Spinks and, with a unanimous decision, took the world title for the third time at 36.

Refusing to retire, he enjoyed a short-lived career as a film actor.

Holding the flame at the 1996 Atlanta Olympics

Always generous with his money, Ali is thought to have earned more than $60m from boxing, but by 1979 he seemed to have little of it left.

A curtailed comeback ended with defeat by Trevor Berbick in December 1981. After losing on points, Muhammad Ali, by now 40 years old, said he would finally retire from the ring.

Later the same year, rumours began to circulate about the state of his health.

Parkinson's Syndrome was eventually diagnosed, a condition only too obvious when, with considerable courage, he lit the 1996 Olympic flame in Atlanta. On that occasion, he was given another gold medal to replace his original, which he had lost.

Still a hero

Today, Ali still travels the world, receiving an ecstatic welcome wherever he appears.

Eubank and the Sports Personality of the Century

The Millennium celebrations saw Ali honoured around the globe. In Britain, BBC television viewers voted him Sportsman of the Century, and he received a similar award from US magazine Sports Illustrated.

The record books will show that Muhammad Ali's boxing career lasted 20 years, during which he won 56 fights and scored 37 knock-outs.

But his achievements have far outstripped that. A dignified, dazzling man, he has touched the world unlike any sportsman before or since.

He is, as they say, a star.