This is classic Muhammad Ali. Ever the showman.

David Beckham posts this picture of Ali together with a famous quote from the iconic boxer.

"Impossible is just a big word thrown around by small men who find it easier to live in the world they’ve been given than to explore the power they have to change it. Impossible is not a fact. It’s an opinion. Impossible is not a declaration. It’s a dare. Impossible is potential. Impossible is temporary. Impossible is nothing.”

Image source, DavidBeckham

How about this one from Lowerhouse CC featuring a padded up Ali wielding the willow with Warwickshire cricketers Dennis Amiss and Bob Willis on a visit to Edgbaston in the sixties. Bob (right) admires a predictably strong bottom hand grip.

BBC World Service

The Reverend Jesse Jackson tells the BBC World Service he has been a personal friend of Ali for more than 40 years and calls him "a defiant man of dignity".

"The US government tried to dethrone him, to disgrace him, but he would not bow.

"He was willing to go to jail for his principles. I've seen some measured sacrifices but with his - in the height of his career - Ali changed the culture.

"Freedom to express oneself - all that comes from the way Ali was willing to express himself."

A film of Muhammad Ali's life was made in 2001, with Hollywood star Will Smith playing the charismatic subject. 

And it's fair to say that Smith - who produced an acting masterclass to make Ali proud - felt the pressure.

"Intellectually, I didn't feel that I possessed what it took to become Muhammad Ali," Smith said in 2001. "I absolutely, positively did not want to be the dude that messed up the Muhammad Ali story."

Image source, Getty Images

Joe Calzaghe
Former two-weight world champion

“Boxing is the hardest sport in the world and in a time when he was champion, it wasn’t a great sport - it was on a bit of a downward spiral but he transcended the sport with his personality.

“People loved him, he was someone completely different, backed it up in the ring and everybody wanted to tune in and watch him fight. 

"He was a superstar. There’ll never be another Muhammad Ali, in a 1,000 years time people will look back and say he was the greatest. 

"He was my inspiration, I tried to copy some of his moves and it is a truly sad day. But I'm proud that my sport of boxing has probably the greatest all-round sportsman of all time."

Former Pakistan cricketer, turned politician Imran Khan says in a series of tweets:, external "Saddened to hear of Muhammad Ali's death - the greatest sportsman of all times. Ali had great talent, was highly intelligent & courageous.

"What set Ali apart from other great sportsmen & what I most admired him for was his refusal to compromise on his belief & value system.

"Sportsmen have a limited career life span in which they can earn & Ali sacrificed it for his beliefs with courage and conviction." 

Image source, Getty Images

Here's Ali stood over Sonny Liston in their second fight of 1965, yelling "Get up and fight, sucker!"

Ali was incensed, with many suggesting the first-round knockout was courtesy of a 'phantom punch' because nobody saw it being delivered.

Either way, this iconic image has been printed millions of times on posters which adorn the walls of boxing gyms, teenage bedrooms and trendy eateries the world over.

Another former world champion, Filipino fighter Manny Pacquiao said: "We lost a giant. Boxing benefitted from Muhammad Ali's talents but not as much as mankind benefitted from his humanity." 

BBC Radio 4

More from legendary broadcaster Sir Michael Parkinson, who has been speaking to the BBC Radio 4 Today programme about Ali. 

"America was divided about Ali, in this country people adored him. All they wanted was to see him, to worship him, to love him and he responded by giving them what they wanted.

"He was maybe the greatest showman I ever interviewed.

"The way he dealt with that appalling Parkinson's disease, external was brave and noble. He never moaned about it and I don't think he ever understood the irony that the greatest boxer of all time was destroyed by his occupation."

Mike Costello
BBC boxing correspondent

"His performance, less heralded, against Cleveland Williams in Houston in 1966, external might just be the best exhibition of heavyweight boxing ever assembled. Three rounds of artistic violence."

Music icon Madonna posted this fabulous picture of her with the great man and wrote on Instagram:, external "This Man. This King. This Hero. This Human! Words cannot express. He shook up the World! God Bless Him."

British boxer Amir Khan with a video tribute on Instagram:, external "A special message about Muhammad Ali, he was a great fighter, an inspirational human being. Let's all keep him and his family in our prayers. RIP

Another of Ali's famous fights was against Ernie Terrell who, in the build-up, refused to call his opponent by his adopted name - instead using his birth name, Cassius Clay.

This angered Ali so much he tormented Terrell in the ring, toying with his opponent like a cat with a mouse rather than deliver a knockout blow.

At various points during the bout, Ali screamed in Terrell's face: "What's my name, Uncle Tom?"

"What could I do?" Terrell later said., external "I could not quit and that meant I had to keep fighting – I could see two or three of him because of the damage and trust me, one is enough." 

Image source, Getty Images

Ed Picson, the executive director of the Philippines' amateur boxing federation, cheered for Ali more than 40 years ago at the Manila bout and says: "He was an icon and an idol to several generations.

"As a boxer he dazzled, mesmerised and inspired awe. There will never be anyone like him. He was, is and will always be the greatest."

There's a theme developing here - of English sports fans getting up in the middle of the night to listen to a fight which didn't involve a domestic fighter. Ali had unparalleled pulling power - one of a select few sportsmen who you'd continually ask your Grandad about as a child.

"Did you ever watch Ali?"; "How good was he?"; "Tell me all about him."

Former BBC Test Match Special producer Peter Baxter with some evocative memories of the great man.

Former Liverpool, Spurs and England goalkeeper is another to recall some nocturnal viewing of Ali fights.

Image source, Getty Images

The measure of a great sportsman is how they respond to defeat. And Ali was emphatic in the way he returned from high-profile defeats to Joe Frazier, Ken Norton and Leon Spinks to settle the score with his adversaries. That world title was his and he did everything to get it back. Invariably he did. Three times.

It was only in his later years, when he was a fading force, that he could not avenge defeat.

Former Spurs and Argentina footballer Ossie Ardiles with his tribute.