Quarry, who twice fought Muhummad Ali, had been admitted into hospital suffering from pneumonia, although he had been battling dementia pugilistica for over 14 years.

He compiled a 53-9-4 record during a career that spanned two decades and first attracted attention by twice defeating former world champion Floyd Patterson in 1967.

Those victories led him to two title shots, the first against Jimmy Ellis for the vacant WBA title in 1968. Quarry lost a 15 round split decision, and a year later he was knocked out in seven rounds by WBC champion Joe Frazier.

Quarry during his first fight with Ali

But Quarry was probably best remembered for his fight with Ali in 1970. Ali was returning from a three and half year exile and found Quarry more than a handful.

The bout was stopped after three rounds, however, because of cuts to Quarry's face and he lost a rematch to Ali two years later, lasting seven rounds this time.

Quarry continued to compete in the upper echelons of the heavyweight class during the early 70s, beating the likes of Earnie Shavers and Ron Lyle, but again lost to Frazier.

He looked a spent force when losing to Ken Norton in 1975, and then fought intermittently until 1983, when he hung up the gloves.

It was soon after he began to suffer from dementia, a result of the heavy punishment he received in the ring.

Despite earning over a million dollars, Quarry was virtually bankrupt by 1992, and made a comeback. His six round loss to unknown Ron Cramner was a sad spectacle, and he retired for the final time.

By the time of his death, Quarry was incapable of looking after himself and required round the clock attention from his brother Mike, himself a former boxer.