The TIME 100

Helen Mirren may have scooped an Oscar for her portrayal of the Queen, head of state of Britain and 15 Commonwealth countries, but it is Elizabeth Windsor who continues to define the role. It was thrust upon her in 1952 by the premature death of her father, and she has not left the stage since. Yet unlike the celebrities and politicians with whom she regularly exchanges pleasantries, the most famous woman in the world has never given an interview.

That reserve was interpreted as indifference in the turbulent months after Princess Diana died, when Britons contemplated burying their monarchy. A decade later the institution is solid, thanks largely to Elizabeth's steady hand. At 81, Her Majesty is still cutting ribbons, laying wreaths, greeting dignitaries and making speeches in a voice that has resisted the temptation to seek acceptance through reinvention. That's the secret of the Queen's success: she understands the need for reforms, such as slimming the costs of her family to the taxpayer and opening her accounts to public scrutiny, but she has never compromised her identity. However, like her beloved corgis and dorgis (a dachshund cross), she occasionally slips the leash, says her second son, Prince Andrew. Once, on a walk, she encountered one of her subjects, who exclaimed, "You look just like the Queen!" "How very reassuring," Her Majesty replied. Many Britons feel the same way.