George IV (George Augustus Frederick; 12 August 1762 - 26 June 1830) was the King of Hanover and the United Kingdom of Great Britain and Ireland from the death of his father, George III, on 29 January 1820 until his own death ten years later. From 1811 until his accession, he served as Prince Regent during his father's relapse into insanity from an illness that is now suspected to have been porphyria.