President Barack Obama paid tribute to Muhammad Ali on Saturday, praising the boxing great’s lasting contribution to American society.

Three-time heavyweight champion Ali died late on Friday night after being admitted to a Phoenix hospital on Monday night.

Ali's stunning upset win over then-heavyweight champion Sonny Liston in 1964 turned him into a household name worldwide. He then famously defeated George Foreman in the Rumble in the Jungle in Kinshasa and Joe Frazier in the Thrilla in Manila in The Philippines. In total Ali made 19 successful title defences during his career.

Colin Hart looks back at one of Ali's greatest fights dubbed 'The Rumble in the Jungle'
But his principled stance and refusal to fight in the Vietnam War - which saw him arrested and later suspended from boxing - made the flamboyant fighter a hero to the masses, and Obama says Ali became "a powerful force for peace and reconciliation around the world".

"Muhammad Ali was The Greatest - period," read a joint statement from the President and the First Lady.

"If you just asked him, he'd tell you. He'd tell you he was the double greatest; that he'd 'handcuffed lightning, thrown thunder into jail'.

"In my private study, just off the Oval Office, I keep a pair of his gloves on display, just under that iconic photograph of him - the young champ, just 22 years old, roaring like a lion over a fallen Sonny Liston.

"I was too young when it was taken to understand who he was - still Cassius Clay, already an Olympic Gold Medal winner, yet to set out on a spiritual journey that would lead him to his Muslim faith, exile him at the peak of his power, and set the stage for his return to greatness with a name as familiar to the downtrodden in the slums of Southeast Asia and the villages of Africa as it was to cheering crowds in Madison Square Garden.

"I am America, he once declared. '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'.

"That's the Ali I came to know as I came of age - not just as skilled a poet on the mic as he was a fighter in the ring, but a man who fought for what was right. A man who fought for us. He stood with (Dr Martin Luther) King and Mandela; stood up when it was hard; spoke out when others wouldn't.

Sir Michael Parkinson spoke to Sky Sports News HQ about his time spent with Ali, a man who he said defined his career
"His fight outside the ring would cost him his title and his public standing. It would earn him enemies on the left and the right, make him reviled, and nearly send him to jail. But Ali stood his ground. And his victory helped us get used to the America we recognise today.

"He wasn't perfect, of course. For all his magic in the ring, he could be careless with his words, and full of contradictions as his faith evolved. But his wonderful, infectious, even innocent spirit ultimately won him more fans than foes - maybe because in him, we hoped to see something of ourselves.

"Later, as his physical powers ebbed, he became an even more powerful force for peace and reconciliation around the world.


Ali 'was a man who fought for us,' says Obama
"We saw a man who said he was so mean he'd make medicine sick reveal a soft spot, visiting children with illness and disability around the world, telling them they, too, could become the greatest.

"We watched a hero light a torch, and fight his greatest fight of all on the world stage once again; a battle against the disease that ravaged his body, but couldn't take the spark from his eyes.

"Muhammad Ali shook up the world. And the world is better for it. We are all better for it. Michelle and I send our deepest condolences to his family, and we pray that the greatest fighter of them all finally rests in peace."