Ali of course changed his name from Cassius Clay and became a Muslim. Today the Ramadhan Foundation paid their own special tribute. 

"From being the greatest boxer that has ever lived to a civil rights champion, a charity worker to a proud Muslim; Muhammad Ali was a unique human being who transformed lives and made the world a better place. 

"When it came to standing up against the unjust war in Vietnam that killed thousands, his conscience wouldn't allow him to join the war and he was sent to prison. 

"But he did not allow this to stop his campaign to speak out against injustice. He left a mark on the world; along with Martin Luther King and Malcolm X he was one of greatest civil rights campaigners. 

"The world is so much a better place for his presence and indeed his spirit will live on for generations to come."     

Indian boxing star Mary Kom said on TV: "I was inspired by him to take up boxing, his struggles and the hard work he took in his boxing career. We feel very, very sad that he is no more. We will always remember his contribution to boxing... I will always remember him and keep him in my heart.”

The front pages from Sunday's newspapers have started to drop and here is the Independent's...

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A family spokesman says Muhammad Ali was admitted to hospital on Monday night.

His cause of death was septic shock due to unspecified natural causes. 

"He did not suffer," said the spokesman. 

A family spokesman says Muhammad Ali's funeral will be held Friday in Louisville, Kentucky.

The funeral will be open to the public and eulogies will be given by former United States of America President Bill Clinton, Billy Crystal and Bryant Gumbel.

The brother of Muhammad Ali, Rahman Ali, pays tribute to a "loving, kind, sweet, good man".

Watch here.

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Former president Bill Clinton released a lengthy statement about three hours after the passing of Ali was announced, on behalf of himself and his Democratic presidential hopeful wife Hillary Clinton.

"Hillary and I are saddened by the passing of Muhammad Ali," the statement read. "From the day he claimed the Olympic gold medal in 1960, boxing fans across the world knew they were seeing a blend of beauty and grace, speed and strength that may never be matched again."

The American civil rights activist and Baptist minister, the Reverend Al Sharpton, has held a church service in memory of Muhammed Ali. 

"Why do we all know a man that was heavyweight champion 45 years ago, and don't know who the heavyweight champion is today," said Sharpton.

"That's what every athlete, every entertainer ought to think about, is what are they going to say about me forty years from now. Why do they honour Ali, and will they honour me? Because he stood for something, and by standing for something, he made us stronger, and he made us better."

"Joe Frazier is so ugly that when he cries, the tears turn around and go down the back of his head."

"Frazier is so ugly he should donate his face to the US Bureau of Wildlife."

"Any black person who's for Joe Frazier is a traitor. The only people rooting for Joe Frazier are white people in suits, Alabama sheriffs and members of the Ku Klux Klan. I'm fighting for the little man in the ghetto."

"It will be a killer and a chiller and a thriller when I get the gorilla in Manila." Before the 'Thrilla in Manila' in 1975.

"I always bring out the best in men I fight, but Joe Frazier, I'll tell the world right now, brings out the best in me. I'm gonna tell ya, that's one helluva man, and God bless him." After the 'Thrilla in Manila', which Ali won.

"I said a lot of things in the heat of the moment that I shouldn't have said. Called him names I shouldn't have called him. I apologise for that. I'm sorry. It was all meant to promote the fight."

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"Why should they ask me to put on a uniform and go 10,000 miles from home and drop bombs and bullets on brown people in Vietnam while so-called Negro people in Louisville are treated like dogs and denied simple human rights?"

"Man, I ain't got no quarrel with them Viet Cong. No Vietcong ever called me nigger."

"I'm not going 10,000 miles from home to help murder and burn another poor nation simply to continue the domination of white slave masters of the darker people the world over."

"Boxing is a lot of white men watching two black men beat each other up."

"Cassius Clay is a slave name. I didn't choose it, and I didn't want it. I am Muhammad Ali, a free name, and I insist people using it when speaking to me and of me."

"Nobody has to tell me that this is a serious business. I'm not fighting one man. I'm fighting a lot of men, showing a lot of 'em, here is one man they couldn't defeat, couldn't conquer. My mission is to bring freedom to 30m black people." Before Ali's fight against Jerry Quarry in 1970.

"I am America. I am the part you won't recognise, but get used to me. Black, confident, cocky. My name, not yours. My religion, not yours. My goals, my own. Get used to me."

"I'm gonna fight for the prestige, not for me, but to uplift my little brothers who are sleeping on concrete floors today in America. Black people who are living on welfare, black people who can't eat, black people who don't know no knowledge of themselves, black people who don't have no future."

"I know I got it made while the masses of black people are catchin' hell, but as long as they ain't free, I ain't free."

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"To make America the greatest is my goal, so I beat the Russian and I beat the Pole. And for the USA won the medal of gold. The Greeks said you're better than the Cassius of old." After winning Olympic light-heavyweight gold medal at the 1960 Games in Rome.

"Sonny Liston is nothing. The man can't talk. The man can't fight. The man needs talking lessons. The man needs boxing lessons. And since he's gonna fight me, he needs falling lessons." Before fighting world heavyweight champion Sonny Liston in February 1964.

"I shook up the world! I shook up the world!" After beating Liston.

"I'll beat him so bad, he'll need a shoehorn to put his hat on." Before beating Floyd Patterson in 1965.

"I never thought of losing, but now that it's happened, the only thing is to do it right. That's my obligation to all the people who believe in me. We all have to take defeats in life." After losing to Ken Norton in 1973.

"I've seen George Foreman shadow boxing and the shadow won." Before knocking out Foreman in their famed 'Rumble in the Jungle' clash in 1974.

"I done wrestled with an alligator, I done tussled with a whale; handcuffed lightning, thrown thunder in jail; only last week, I murdered a rock, injured a stone, hospitalised a brick; I'm so mean I make medicine sick." Before the 'Rumble in the Jungle'

"It's just a job. Grass grows, birds fly, waves pound the sand. I beat people up."

"The fight is won or lost far away from witnesses - behind the lines, in the gym, and out there on the road, long before I dance under those lights."

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"It's hard to be humble when you're as great as I am."

"Float like a butterfly, sting like a bee, his hands can't hit what his eyes can't see."

"I'm the boldest, the prettiest, the most superior, most scientific, most skilfullest fighter in the ring today."

"If you even dream of beating me, you better wake up and apologise."

"Will they ever have another fighter who writes poems, predicts rounds, beats everybody, makes people laugh, makes people cry and is as tall and extra pretty as me?"

"The fact is, I was never too bright in school. I ain't ashamed of it, though. I mean, how much do school principal's make a month? I said I was 'The Greatest', I never said I was the smartest!"

"At home I am a nice guy - but I don't want the world to know. Humble people, I've found, don't get very far."

Former world super-middleweight and light-heavyweight champion Joe Calzaghe: 

"Ali was my inspiration.

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

"There'll never be another Muhammad Ali. He was a superstar."

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You can read more tributes to Muhammad Ali here.

Muhammad Ali made four appearances on Sir Michael Parkinson's chat show in the 1970s and 1980s.

So what was it like interviewing Ali? Watch Parkinson reminisce about their encounters...