George IV as Prince of Wales was Regent from 1810 to 1820 during his father’s period of insanity. He had several mistresses and in 1785 had secretly married a Catholic widow Maria Fitzherbert in contravention of the Act of Settlement and the Royal Marriage Act. They had at least two illegitimate children. Unlike his father he was extravagant with money and became badly in debt. He loved the fine things in life and undertook rebuilding of Buckingham Palace and Windsor Castle. Architect John Nash and others created many fine buildings in London, Brighton, Bath and Cheltenham during the ‘Regency Period’.
He was forced to deny his marriage with Mrs Fitzherbert and in return for paying off his debts officially marry Caroline of Brunswick whom he detested, so much so that when he became King George IV on the death of his father in 1820 he refused to let her attend his coronation. They had one child Princess Charlotte, but George refused to recognise Caroline as Queen and tried several times to annul his marriage to her. She died in 1821 claiming on her death bed that she had been poisoned.
George IV paid a state visit to Ireland but initially refused to support Catholic emancipation until 1829 when encouraged by the Duke of Wellington the Catholic Relief Act was passed. .He visited Scotland in 1822, the first monarch to do so since Charles II, and encouraged by Sir Walter Scott wore full Highland regalia leading to a revival of Scottish tartan dress that had been banned after the Jacobite Rebellions.
His heavy drinking, indulgent lifestyle and taste for huge amounts of food made him obese, and he became an unpopular figure of ridicule when he appeared in public. He suffered from gout and towards the end of his life became mentally unstable. He died of a heart attack at Windsor Castle in 1830. His only legitimate daughter Charlotte had died in childbirth in 1817 and next eldest brother Frederick died in 1827 so he was succeeded by his younger brother William IV (Royal family history: www.britroyals.com)