The last and only other time St Paul's Cathedral was the venue for a queen's Diamond Jubilee celebration, the Queen in question was so frail the service had to be held outside because she could not manage the steps.
Victoria, suffering from rheumatism, was confined to her carriage as representatives from the British Empire, procession troops and two choirs gathered in front of the famous church in 1897 for the brief open air service.
One hundred and fifteen years later, her great-great granddaughter Queen Elizabeth II took the two flights, totalling 24 steps, leading her through the Great West Door, without any problem at all.
She is still sprightly at 86 - despite being some eight years older than her Diamond Jubilee predecessor was at the time.
Victoria was without her beloved Prince Albert, who had died many years earlier.
The Queen too cut something of a solitary figure at today's service with the absence of the Duke of Edinburgh.
She walked through the majestic cathedral alone across the black and white stone floor, a few feet behind the Lord Mayor bearing the ceremonial Pearl Sword.
Seating plans were adjusted and the Queen's ornate chair was placed next to the Prince of Wales, rather than in a central position where she would have sat with the Duke of Edinburgh.
Inside the congregation could hear huge cheers from the crowds outside as the Duke and Duchess of Cambridge and Prince Harry arrived, but the loudest shouts of all were reserved for the Jubilee Queen, who shimmered in a mint green dress.
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