Muhammad Ali dies aged 74

Muhammad Ali, one of the greatest athletes in history, has passed away at the age of 74.

The former professional boxer, generally considered as the best heavyweight of all time, succumbed to a 32-year battle with Parkinson's disease after being hospitalised with respiratory problems.

Ali suffered for years from Parkinson's disease, which ravaged his body but could never dim his larger-than-life presence.

Ali during a 1964 interview with CBS' Eric Sevareid. Source: Getty

He was hospitalised in Phoenix with respiratory problems earlier this week, and his family gathered around him.

He died Friday night, according to a statement from the family.

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Family spokesman Bob Gunnell has released a statement announcing the death of the three-time heavyweight champion.

The funeral will take place in his hometown of Louisville, Kentucky.

"The Ali family would like to thank everyone for their thoughts, prayers, and support and asks for privacy at this time," the statement said.

Born Cassius Marcellus Clay Jr, Ali's feats of brilliance in the square circle were only matched by his larger-than-life personality.

In a time when most athletes stood back and let their mangers do the talking, Ali stole the spotlight with his outlandish claims and entertaining banter.

He dubbed himself "The Greatest" and "The People's Champion" and certainly lived up those expectations, crowned "Sportsman of the 20th Century" by Sports Illustrated and "Sports Personality of the 20th Century" by the BBC.

Bursting onto the scene at the tender age of 22, he shocked the world by upsetting Sonny Liston to win the world heavyweight championship in 1964.

It was in the lead-up to this fight that some of Ali's most famous taunts come from. He declared that he would "float like a butterfly and sting like a bee," and in regard to Liston, "Your hands can't hit what your eyes can't see."

Ali v Liston. Image: Getty

To this day, he remains the only three-time lineal World Heavyweight Champion, and took part in some of boxing's most famous and historic bouts.

His rivalry with Joe Frazier took on epic proportions, culminating in the 'Thrilla in Manila', and his 1974 knockout victory over George Foreman, dubbed the 'Rumble in the Jungle', is widely regarded as the greatest sporting event of the 20th Century.

Ali defeated every heavyweight boxer of his era, often referred to as the 'Golden Age' of the sport.

He was named "Fighter of the Year" by Ring Magazine more times than any other fighter, and was involved in the most Ring Magazine "Fights of the Year". He is in the International Boxing Hall of Fame and holds wins over seven other inductees.

While he was loved and feared for his feats inside the ring, the values he displayed outside it were just as noteworthy.

Ali v Frazier. Image: Getty

He strongly opposed America's involvement in the Vietnam War and refused to conscript to the US military as a result.

While he was stripped of his world titles and gave up boxing for four years, his actions as a conscious objector made him a cultural icon.

He went on to drastically alter society's view of African American athletes by embracing racial pride and constantly questioning the white establishment.

Ali and wife Lonnie in 2012. Image: Getty

As his career declined, he started to suffer from noticeable vocal stutters and hand tremors. After finally giving in to pleas to retire in 1981, his last few fights were said to have contributed to his Parkinson's Syndrome, a disease common in head trauma victims.

Ali's bout with Parkinson's led to a gradual decline in his health, but he tried to remain active and was honoured with the task of lighting the flame at the 1996 Olympic Games in Atlanta.

He leaves behind wife Yolanda "Lonnie" Williams, as well as seven daughters and two sons.

- with AAP