George IV or George Augustus Frederick (12 August 1762 - 26 June 1830) was king of the United Kingdom of Great Britain and Ireland and Hanover from 29 January 1820 until his death. He had earlier served as The Prince Regent when his father, George III, suffered from a relapse into insanity from an illness that is now suspected to have been porphyria. The Regency, George's nine-year tenure as Prince Regent, which commenced in 1811 and ended with George III's death in 1820, was marked by victory in the Napoleonic Wars in Europe.