The Queen chose to mark the occasion privately and quietly at her Sandringham Estate in Norfolk, but in York and London the gun salutes that cracked through the noon air made sure her anniversary did not go unnoticed.
Snow was falling in York’s Museum Gardens as the Saluting Troop from 88 (Arracan) Battery, 4 Regiment Royal Artillery, fired 21 volleys. The city is the only saluting station in the North, having been given the honour to mark its 1,900th anniversary in 1971.
Simultaneously in London, 41 volleys were fired by the King’s Troop Royal Horse Artillery in Green Park, followed an hour later by a 62-gun salute at the Tower of London.
The longest-reigning sovereign in British history acceded to the throne 66 years ago, on February 6 1952, upon the death of her father, King George VI.
For her, yesterday was a chance to mourn his death rather than celebrate her succession.
It was at Sandringham, where she has been spending her annual winter break, that the King died in his sleep. He had been suffering from lung cancer.
Princess Elizabeth, then 25, was in Kenya on a Commonwealth tour with the Duke of Edinburgh when she learned of the news. She returned home a queen.
This year will be a busy one for the Windsors, with two weddings and two new great-grandchildren for the Queen.