The death of Muhammad Ali, the former heavyweight champion known as much for his political activism as his boxing brilliance, triggered a worldwide outpouring of affection and admiration for one of the best-known figures of the 20th century.
Ali, who had long suffered from Parkinson's syndrome which impaired his speech and made the once-graceful athlete almost a prisoner in his own body, died on Friday at age 74.
The cause of death was septic shock due to unspecified natural causes, a family spokesman said on Saturday. Ali was admitted to a Phoenix-area hospital, HonorHealth, with a respiratory ailment on Monday.
"He’ll be remembered as a man of the world who spoke his mind and wasn’t afraid to take a chance and went out of his way to be a kind, benevolent individual that really changed the world," the family spokesman, Bob Gunnell, said at a news conference in Scottsdale, Arizona.
Despite Ali's failing health, his youthful proclamation that he was "the greatest" rang true until the end for millions of people around the world who respected him for his courage both inside and outside the ring.
Along with a fearsome reputation as a fighter, Ali spoke out against racism, war and religious intolerance, while projecting an unshakeable confidence that became a model for African-Americans at the height of the civil rights era and beyond.
Stripped of his world boxing crown for refusing to join the U.S. Army and fight in Vietnam, Ali returned in triumph by recapturing the title and starring in some of the sport's most unforgettable bouts.
"I think when you talk about Muhammad Ali, as great an athlete, as great a boxer as he was, he was the greatest boxer of all time, he means so much more to the United States and the world," said Ali's long-time friend, boxing promoter Bob Arum.
"He was a transformative figure in our society."
Bursting onto the boxing scene in the 1960s with a brashness that threatened many whites, Ali would come to be embraced by Americans of all races for his grace, integrity and disarming sense of humor.
"In the end, he went from being reviled to being revered," civil rights leader the Rev. Jesse Jackson told CNN on Saturday.
Pam Dorrough, a tourist in New York's Times Square, admired Ali's refusal to apologize for what he believed.
"The confidence - and I know everybody thought it was an arrogance about him - he always projected a confidence," she said. "And he stood by that."
President Barack Obama, the first African-American to reach the White House, said Ali was "a man who fought for us" and placed him in the pantheon of civil rights leaders Martin Luther King Jr and Nelson Mandela.