Never in British history has a monarch had so long to prepare for the role. Seven decades after he became heir to the throne aged three, King Charles III assumed the title following the death of his mother, Queen Elizabeth II, on Thursday.
Nor has a monarch arrived having previously revealed so much of his opinions and emotional life. This pensive man, once demonised after his separation from the late Diana, Princess of Wales, now replaces the longest-serving and arguably most perfectly cast sovereign that the country has ever had.
His reign will test him. It may also test whether the constitutional monarchy is compatible with a less neutral incumbent. Jonathan Dimbleby, Charles’s authorised biographer, once predicted he would “go well beyond what any previous constitutional monarch has ever essayed”.