The life of

Born Cassius Marcellus Clay Jr in Louisville, Kentucky, in 1942, a 12-year-old Ali took up boxing at the advice of a police officer following the theft of his bike.

The officer, Joe E Martin, also served as a trainer at a local gym and prepared Ali for his amateur boxing debut in 1954 – a bout he won by a split decision.

Ali began to enjoy a degree of success in regional boxing events and won back-to-back Intercity Golden Gloves tournaments in 1959 and 1960, as well as the Amateur Athletic Union national title.

However, it was a gold medal-winning performance at the 1960 Olympic Games in Rome that won Ali a more global audience.

A rising star of the sport, he swiftly turned professional and showed no signs of slowing down in his rapid ascent to boxing's elite.

The self-assured Ali defeated British champion Henry Cooper in 1963, before knocking out Sonny Liston to become WBA and WBC heavyweight champion of the world the following year, and subsequently defended that title against the same opponent.

In total, Ali amassed 29 consecutive professional victories before serving a three-and-a-half-year suspension for refusing a call-up for military service.

Ali had earlier joined the Muslim group Nation of Islam – prompting his change of name – and cited his religious beliefs and opposition to US involvement in the Vietnam War as his reasons for rejecting the call.

Ali was stripped of his title but made a winning comeback upon his return to the ring in 1970, knocking out Jerry Quarry.

The now 29-year-old Ali was soon topping bills once again, but suffered the first defeat of his career in 1971 – losing to Joe Frazier by unanimous decision in what would become known as 'The Fight of the Century'.

The pair met again in 1974 – Ali this time coming out on top, before going on to reclaim the WBC and WBA titles from George Foreman at 'The Rumble in the Jungle'.

Ali successfully defended those belts on 10 occasions, including in another brutal battle with Frazier at 1975's 'Thriller in Manila', before his career entered a decline.

A defeat to Leon Spinks cost him his titles and, although he bounced back to beat the same opponent seven months later, subsequent losses to Larry Holmes and Trevor Berbick brought a disappointing curtain down on a glittering career.

Ali announced in 1984 that he had Parkinson's disease but continued to devote himself to charity work and was recognised with a number of individual accolades, including Sports Illustrated's Sportsman of the Century.

He was the final torchbearer at the 1996 Olympic Games in Atlanta and played a role in raising the Olympic flag at London 2012, but became a less visible public presence in his later years.