Vatican City, Rome, Italy. 14th April, 1951. Princess Elizabeth (later Queen Elizabeth II) and the Duke of Edinburgh pose for a group photograph with their entourage and Vatican knights and Swiss guards following their talk with pope Pius XII. [Getty Images]

Vatican City, Rome, Italy, 14th April, 1951, Princess Elizabeth (later Queen Elizabeth II) and the Duke of Edinburgh pose for a group photograph with their entourage and Vatican knights and Swiss guards following their talk with pope Pius XII (Photo by Popperfoto via Getty Images/Getty Images) — see more

Vatican City, Rome, Italy, 14th April, 1951, Princess Elizabeth (later Queen Elizabeth II) and the Duke of Edinburgh pose for a group photograph with their entourage and Vatican knights and Swiss guards following their talk with pope Pius XII (Photo by Popperfoto via Getty Images/Getty Images)