George III ruled longer than any British monarch before him, and for two centuries the private papers that might explain his notorious bouts of madness stayed locked in the Royal Archives. Historian Robert Hardman gets the first extensive access to that collection, working through letters, medical records, and household accounts to reconstruct a king better known for losing America and shouting at trees than for what he actually did on the throne. The film follows his early reign as a reforming, hands-on ruler, then tracks the physical decline that later doctors and biographers have argued over for years, from porphyria theories to plain psychiatric illness. Interviews with historians and archivists sit alongside readings from the newly opened documents, letting George's own words carry parts of the story. What emerges is a monarch shaped as much by family strain, war, and the pressures of empire as by whatever illness eventually took his mind. The archive material is the reason this account differs from earlier ones.