Biography: Charles III (Charles Philip Arthur George) is King of the United Kingdom and 14 other Commonwealth realms. He acceded to the throne on 8 September 2022 upon the death of his mother, Queen Elizabeth II. As Duke of Cornwall and Duke of Rothesay from 1952 to his accession, he was the oldest and the longest-serving heir apparent in British history, and the longest-serving Prince of Wales, having held the title from 26 July 1958 until his accession. At 73 years of age, Charles is also the oldest person ever to assume the British throne, a record previously held by William IV at age 64.