Elizabeth II has lived through the Abdication the Blitz & World War Two the sex & spy scandals of the swinging sixties the Cold War & the nuclear threat & the Fall of the Berlin Wall. She has known 11 US Presidents including JFK & Ronald Reagan & other world leaders like President Mandela & Pope John XXII. Her Prime Ministers have ranged from Winston Churchill & Margaret Thatcher to David Cameron the last only ten years older than her grandson. Her own family experiences a mixture of happiness & crisis weddings & divorces & in the case of Diana violent death have been lived in the glare of tabloid headlines. More than 2 billion people watched the wedding of her grandson Prince William to Catherine Middleton in 2010 shortly before she made the first State Visit to Ireland by a British monarch for 100 years. Our world has changed more in her lifetime than in any of her predecessors: the Queen has remained a calm presence at the centre earning the respect of monarchists & republicans. How has she done it?