The Queen surpassed her great-great-grandmother, Queen Victoria, to become the longest-lived British monarch in December 2007, and the longest-reigning British monarch on 9 September 2015. She was celebrated in Canada as the "longest-reigning sovereign in Canada's modern era". (King Louis XIV of France reigned over part of Canada for longer.) She is the longest-reigning queen regnant in history, the world's oldest reigning monarch and second-longest-serving current head of state after King Bhumibol Adulyadej of Thailand.
In age of monarchs, what is the rank of Elizabeth's reign?
{'text': "world's oldest", 'answer_start': 403}