When she became Queen at the age of 25, few could have imagined the lengthy and successful reign that lay ahead. Now aged 92, Her Majesty has just celebrated an extra-special Christmas with her family at Sandringham. This year has seen the doting grandmother and great-grandmother welcome two new great-grandchildren - Prince Louis and Lena Tindall - as well as attending the weddings of her grandson Prince Harry, who married Meghan Markle in May, and most recently Princess Eugenie, who tied the knot to Jack Brooksbank in October, with both couples deciding to marry at St George's Chapel in Windsor. Next year will be just as exciting, with Harry and Meghan's first child due in the spring.
Looking back, The Queen's coronation on 2 June 1953, brought together pomp, pageantry and solemn ritual. More than 8,000 guests packed into Westminster Abbey to witness what was heralded as "a new Elizabethan age".
Her youth added vitality to a monarchy that had been severely tested by World War II. Prime Minister Winston Churchill predicted that Britain was about to enter a second golden age to rival that enjoyed under her great namesake.
The Queen, seen here with President JF Kennedy and his wife Jackie, has outlasted 12 prime ministers and welcomed successive US presidents.
She combined the early years of her reign with raising a young family. Prince Charles arrived in 1948 and Princess Anne two years later. Her two younger children Andrew and Edward, seen here, were born in 1960 and 1964.
There was more happiness when she invested Prince Charles as Prince of Wales in 1969.
With Britain's other Iron Lady Margaret Thatcher three months after she became prime minister.
The first of her children to marry was Princess Anne who wed Captain Mark Phillips in 1973 and gave the Queen her first grandchildren, Zara and Peter.
In 1977, came her Silver Jubilee marking 25 years on the throne. The sovereign repeated her pledge, made aged 21, to devote herself to the service of her people. "Although that vow was made in my salad days when I was green in judgement, I do not regret nor retract one word of it."
Part of her appeal lies in her desire to see and be seen by her subjects across the globe. The Queen pictured in 1963 in Australia, the kingdom she has visited 16 times.
Queen Elizabeth II became the first British monarch to visit mainland China in 1986.
The fairytale wedding of Prince Charles and Princess Diana seemed to augur well, bringing allure, youth and modern glamour to the family.
While the young Princess was a barnstorming success with the public, her marriage faltered.
She and Charles struggled to understand each other and divorced in 1996, as did two of his siblings.
A year later, the Queen had to comfort her shattered grandsons when their beloved mother was killed. It was one of the few times that the monarch was severely criticised for not reading the public mood. She responded by appearing on TV to pay tribute to Diana as "an exceptional and gifted human being", praising the Princess for her devotion to others and to her children.
Whatever personal losses the Queen has suffered, the royal roadshow has gone on. The matriarch is seen here in Ottawa on one of her many tours of Canada.
A truly regal and exotic reception in one of her tiny realms Tuvalu in 1982.
Being welcomed wearing a cloak of Kiwi feathers to signify her title of 'The Rare White Heron in Maori country, Gisbourne, New Zealand.
The storms that had beset the monarchy subsided with the marriage of Prince Charles to his longtime love Camilla in 2005, giving his mother peace of mind.
The tireless sovereign stays young by keeping up with passions such as horseriding.
She is also an enthusiastic – and very occasionally – noisy follower of horseracing.
The Queen has for years trained and bred racehorse and starts every morning by perusing the Racing Post.
Her grandson's wedding to Kate Middleton in 2011 was another joyous occasion for Her Majesty, giving her reassurance that her legacy is in good hands.
In recent years the nation's favourite great-grandma has relaxed and allowed herself to show off a twinkly sense of humour. At the 2012 Olympics opening ceremony, she surprised the whole world by starring in a sketch with Bond star Daniel Craig.
In 2012, for her Diamond Jubilee, record crowds lined the streets of London to paid tribute to the monarch whose dignified, steady leadership has shaped Britain for more than 60 years.