Queen Elizabeth II is Britain's longest-serving monarch, having reigned for 65 years since ascending the throne in 1952.
As of October 2016, she also became the world's longest currently reigning monarch and head of state.
In October 1951, Princess Elizabeth and Prince Philip made their historic first visit to Canada.
With her father King George VI gravely ill, the Princess took his place and led a major royal tour for the first time, just a few months before ascending to the throne herself.
The Canadian Globe and Mail newspaper reported that "there was that touch of fairytale atmosphere about her arrival", as the couple were greeted by a crowd of 15,000 well-wishers at Montreal Airport.
With security on high alert, the royal couple were accompanied by security officers and a team of Royal Canadian Mounties wherever they went.
For the next five weeks they drew record crowds, with millions of people lining streets as the Royal motorcade travelled back and forth across the country.
According to Life Magazine journalist Allan Michie, Princess Elizabeth "was not prepared for either the size or the warmth or the vociferousness of her welcome, or for a newly experienced familiarity in the approach to royalty."
Although highly nervous upon her arrival to Canada, the Princess gained confidence throughout the trip, growing comfortably into her role as a future head of state.
Upon her return to England in November 1951, Elizabeth declared of her Canadian trip:
"I am sure that nowhere under the sun could one find a land more full of hope, of happiness and of fine, loyal, generous-hearted people."
"They have placed in our hearts a love for their country and its people which will never grow cold and which will always draw us to their shores."
This black and white landscape photograph features Princess Elizabeth and Prince Philip together with members of the Royal Canadian Mounted Police.
Following the five week tour, the members of the Royal Canadian Mounted Police that had accompanied the royal couple were invited to London in gratitude for their service.
The signed photograph was then presented to Assistant Commissioner M.F.E. Anthony during a ceremony at Clarence House.
The photograph measures 28 x 36cm, and features the signatures "Elizabeth" and "Philip", along with the date "1951" written in the Princess' hand.
The photograph includes light yellowing to white margins, with a few light stains to verso.
With protocol stating that members of the royal family do not sign autographs, Queen Elizabeth II's signature remains both highly rare and sought-after by collectors.
This superb signed photograph recalls a seminal moment in the Queen's life, as she represented her country abroad on a major trip for the first time, marking the beginning of a lifetime of service.