Angelo Dundee, who is best known for the more than two decades he spent as boxer Muhammad Ali’s trainer, died on Wednesday aged 90.

Dundee worked with 15 world champions, including Sugar Ray Leonard, George Foreman and Jimmy Ellis but it is his work with Ali that stands out the most.

The Miami Herald reported that Dundee died of a heart attack in a rehabilitation centre after initially being admitted to the hospital with a blood clot.

Dundee travelled the world with Ali and worked with him in his most famous fights, including ‘The Rumble in the Jungle’ against Foreman in 1974.

Together they crafted the “rope-a-dope” technique which helped Ali dethrone Foreman in what was called the fight of the year by The Ring Magazine.

Dundee, who was born in Philadelphia, attended Ali’s 70th birthday party last month in Louisville, Kentucky.

His son, Jimmy, told US television broadcaster ESPN that Dundee died with his family beside him.

“It was the way he wanted to go. He did everything he wanted to,” Jimmy Dundee told ESPN.

Dundee was considered a quick thinker and the best fight strategist in the sport. He began working with Leonard in 1976 before helping Foreman win the heavyweight title in 1994 at the age of 45.

Dundee’s death comes as questions surround the health of Ali. In November, the heavyweight great was briefly hospitalised in Phoenix, where doctors treated him for dehydration.

That came a few days after Ali attended the funeral of his old rival Joe Frazier, who died of liver cancer in Philadelphia on November 8.