The longest-serving monarch in British history is Queen Elizabeth II. She ascended the throne on February 6, 1952, following the death of her father, King George VI. Queen Elizabeth II surpassed the previous record set by her great-great-grandmother, Queen Victoria, on September 9, 2015. Her reign witnessed significant historical events, including the decolonization of Africa and the Caribbean, the Cold War, and changes in the monarchy's role in modern Britain. Elizabeth's commitment to public service and constitutional duties, combined with her adaptability to social changes, contributed to her status as a beloved and respected figure in British and Commonwealth history.