Christian VII was King of Denmark and Norway and Duke of Schleswig and Holstein from 1766 until his death in 1808. He was affected by mental illness and was only nominally king for most of his reign. His royal advisers changed depending on the outcome of power struggles. From 1770 to 1772, his court physician Johann Friedrich Struensee was the de facto ruler of the country and introduced progressive reforms signed into law by the king. Struensee was deposed by a coup in 1772, after which the country was ruled by Christian's stepmother, Queen Dowager Juliane Marie of Brunswick-Wolfenbüttel, his half-brother Hereditary Prince Frederick, and the Danish politician Ove Høegh-Guldberg. From 1784 until Christian VII's death in 1808, Christian's son, later Frederick VI, acted as unofficial prince regent.