He proclaimed himself "The Greatest", and at the height of his powers few dared to disagree. But Muhammed Ali, who died on June 3rd after a protracted battle with Parkinson's disease, was much more than just a boxer, even if he was the greatest boxer to have ever graced the ring.
For some he was a loudmouth, too full of his own giant ego, but as Ali once said: "I ain't conceited, I'm just convinced." Perhaps more than any others, those words encapsulate a man who was fuelled by an unflinching self-belief, not just in his abilities in the boxing ring, but in his rights as a black man in America. He talked the talk, but he also walked the walk.
In fact Ali was more popular in Britain than in his native America, where opinion about him divided the nation. While many admired his willingness to stand up for his beliefs, others never forgave him for turning to Islam or refusing the Vietnam War draft.
His popularity in Britain was heightened by four memorable interviews on classic BBC chat show Parkinson, where he verbally sparred with host Michael Parkinson and other guests. He showed himself to be intelligent, charming, with a razor-sharp sense of humour, but also fierce in defence of the things he held dear. He was as much a 20th century philosopher as a truly gifted pugilist.
But for all his other talents, it was in the ring that Ali first caught the public eye. Born Cassius Marcellus Clay in Louisville Kentucky in 1942, it was a chance encounter with a local cop which set him on the road to international fame. At the age of 12 he reported his bicycle stolen and confidently told the cop that when he found the culprit he would "whup him"!
That cop, Joe Martin, trained fighters at the local gym and suggested young Cassius should learn to box if he was going to "whup" anyone. Right from the outset he displayed a prodigious talent and a fierce determination to win. His amateur career flourished and in 1960 he was selected for the US team at the Rome Olympics, where he won gold to become Olympic light-heavyweight champion.
When the team returned to New York he received a hero's welcome, but back home in Kentucky he was refused a table in a segregated restaurant because of his colour – a moment he later described as a turning point in his life.
Turning pro at 18, he notched up a string of wins over increasingly tough opponents, dominating them with his lightning fast speed and remarkable ability to absorb a punch. Though clearly a heavyweight, he danced around the ring like a lightweight. Only once did he seem vulnerable, when he was floored in the fourth round by Henry Cooper during a bout in London. Despite looking visibly shaken, Ali got up and won the bout in the next round when a deep cut forced Cooper's retirement.
By now Clay had also earned a reputation for showmanship both in the ring and outside it, where he would often confidently predict the round in which he would win a bout, often in poetry. Nicknamed 'the Louisville Lip', it was all part of his super-confident persona and unshakeable self-belief... and it sold more tickets for his fights.
In 1964 he took on formidable world champion Sonny Liston, branding him an "ugly old bear". The boxing press gave him little chance against the hugely experienced Liston, but he ran rings against the older, and possibly complacent, boxer. Liston lasted six punishing rounds, but could not, or would not, get off his stool for the seventh.
It was as Heavyweight World Champion that Cassius Clay became Muhammed Ali, announcing that he had embraced the Nation of Islam and thrown off his "slave name". In the run-up to a 1967 championship bout, his opponent Ernie Terrell often referred to Ali as Cassius Clay. Handing out a 15-round battering which many said he could have ended sooner, Ali repeatedly shouted in Terrell's face "What's my name Uncle Tom?"
Eight more title defences followed, but by now large sections of the American public had turned against Ali, who used his fame as a platform to speak out on race issues. When he refused the Vietnam draft he was stripped of his title and jailed for five years, the sentence later quashed on appeal. As the war dragged on, claiming thousands of American lives, many came to believe Ali had been right when he said "I ain't got no quarrel with them Vietcong."
After an enforced three-year absence from the ring, Ali was allowed to return in 1970, with a win over Jerry Quarry. But his legendary speed had slowed and the following year he suffered the first defeat of his professional career at the hands of Joe Frazier. Many wrote him off as a spent force, but they were wrong.
Perhaps Ali's greatest moment came in 1974 when he defeated George Foreman in Zaire in the so-called 'Rumble in the Jungle'. For eight punishing rounds Ali soaked up the punches of his younger and much larger opponent, often leaning back on the ropes with his defences down. Then, at the end of the eighth, he seemed to suddenly spring to life, flooring the exhausted Foreman with an immaculate combination. Speaking afterwards he called the tactic "rope-a-dope".
At 32 he had regained the world title for the second time, and a year later gained revenge against Frazier in a brutal 14-round encounter, the 'Thriller in Manilla'. In 1978 he lost his title to Olympic champion Leon Spinks, 12 years his junior, but won it back for an unprecedented third time in the return bout eight months later.
Refusing to retire, perhaps because he needed the money, Ali fought on but lost his title to former sparring partner Larry Holmes in 1980 and finally hung up his gloves in 1981, at the age of 40. By the mid-eighties rumours of his failing health were widespread, with a diagnosis of Parkinson's disease eventually made public.
If anything it only seemed to increase his popularity, as he battled the condition with courage and dignity. He continued to travel the world, always receiving a rapturous welcome. In 2000, BBC Viewers voted Ali their 'Sports Personality of the Century', and he received a similar accolade from Sports Illustrated in America, seen as long overdue recognition in his home nation.
In a remarkable 21-year professional career, he won 56 fights and lost just five. But perhaps his greatest impact was outside the ring, where this larger-than-life sporting great was an inspiration to millions.