LONDON (AFP) - Forty-six years after their memorable world heavyweight title fight, Muhammad Ali and Sir Henry Cooper were reunited on Friday in the genteel surroundings of Windsor Castle. The pair took a lap of honour in an open-top Range Rover around the Castle Arena, the venue for the ongoing European equestrian championships. Ali, who was then known as Cassius Clay, fought great British hope Cooper for the first time at Wembley in London in 1963, when Cooper famously floored the great American in the fourth round. Clay's corner men secured a longer break than usual after trainer Angelo Dundee increased a tear in Clay's gloves before the American went on to stop Cooper in round five. The 67-year-old Ali, who also plans a visit to Ireland where his great-grandfather was born, has lived with Parkinson's Disease since 1984. He is on a short trip to the UK, raising awareness for his Alltech-Muhammad Ali Centre Global Education and Charitable Fund Ali, wearing a black suit and dark glasses, received a standing ovation from the crowd, albeit a disappointing attendance way below the 9,000 capacity. He responded by waving to them, supported by Cooper, who spoke to him throughout. British boxer Amir Khan was also at the event.