Query: George III was succeeded by his son, George IV.

Relevant passages:
George III of the United Kingdom <=SEP=> George III ( George William Frederick ; 4 June 1738 -- 29 January 1820 ) was King of Great Britain and Ireland from 25 October 1760 until the union of the two countries on 1 January 1801 , after which he was King of the United Kingdom of Great Britain and Ireland until his death . He was concurrently Duke and prince-elector of Brunswick-Lüneburg ( `` Hanover '' ) in the Holy Roman Empire until his promotion to King of Hanover on 12 October 1814 . He was the third British monarch of the House of Hanover , but unlike his two predecessors he was born in Britain , spoke English as his first language , and never visited Hanover .   His life and with it his reign , which were longer than any other British monarch before him , were marked by a series of military conflicts involving his kingdoms , much of the rest of Europe , and places farther afield in Africa , the Americas and Asia . Early in his reign , Great Britain defeated France in the Seven Years ' War , becoming the dominant European power in North America and India . However , many of Britain 's American colonies were soon lost in the American War of Independence . Further wars against revolutionary and Napoleonic France from 1793 concluded in the defeat of Napoleon at the Battle of Waterloo in 1815 .   In the later part of his life , George III had recurrent , and eventually permanent , mental illness . Although it has since been suggested that he had the blood disease porphyria , the cause of his illness remains unknown . After a final relapse in 1810 , a regency was established , and George III 's eldest son , George , Prince of Wales , ruled as Prince Regent . On George III 's death , the Prince Regent succeeded his father as George IV .   Historical analysis of George III 's life has gone through a `` kaleidoscope of changing views '' that have depended heavily on the prejudices of his biographers and the sources available to them . Until it was reassessed in the second half of the 20th century , his reputation in the United States was one of a tyrant ; and in Britain he became `` the scapegoat for the failure of imperialism '' .

George IV of the United Kingdom <=SEP=> George IV ( George Augustus Frederick ; 12 August 1762 -- 26 June 1830 ) was King of the United Kingdom of Great Britain and Ireland and of Hanover following 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 final mental illness .   George IV led an extravagant lifestyle that contributed to the fashions of the Regency era . He was a patron of new forms of leisure , style and taste . He commissioned John Nash to build the Royal Pavilion in Brighton and remodel Buckingham Palace , and Sir Jeffry Wyattville to rebuild Windsor Castle .   His charm and culture earned him the title `` the first gentleman of England '' , but his poor relationship with both his father and his wife , Caroline of Brunswick , and his dissolute way of life , earned him the contempt of the people and dimmed the prestige of the monarchy . He even forbade Caroline to attend his coronation and asked the government to introduce the unpopular Pains and Penalties Bill in a desperate , unsuccessful attempt to divorce her .   For most of George 's regency and reign , Lord Liverpool controlled the government as Prime Minister , with little help from George . His ministers found his behaviour selfish , unreliable and irresponsible . At all times he was much under the influence of favourites . Taxpayers were angry at his wasteful spending at a time when Britons were fighting in the Napoleonic Wars . He did not provide national leadership in time of crisis , nor act as a role model for his people . Liverpool 's government presided over Britain 's ultimate victory , negotiated the peace settlement , and attempted to deal with the social and economic malaise that followed . After Liverpool 's retirement , George was forced to accept Catholic emancipation despite opposing it . His only child , Princess Charlotte , died before him in 1817 and so he was succeeded by his younger brother , William .