King of Great Britain and Ireland and of dependencies overseas, King of Hanover (1820–30). As regent (1811–20) and later king, he led a dissolute life and was largely responsible for the decline in power and prestige of the British monarchy in the early 19th century. The eldest son of George III, he cultivated the friendship of Charles James Fox and other Whigs. In 1785 he secretly and illegally married a Roman Catholic widow, Maria Fitzherbert (1756–1837). Ten years later he reluctantly married Caroline of Brunswick, and separated from her immediately after the birth of their only child, Princess Charlotte. George III became increasingly senile at the end of 1810 and in the following year the prince was appointed regent. He gave his support to the Tories, but soon quarrelled with them too, leaving himself without a large personal following in Parliament. His reign saw the passage of the Catholic emancipation Act (1829). His attempt to divorce Caroline for adultery in 1820 only increased his unpopularity. He was a leader of taste, fashion, and the arts, and gave his name to the Regency period. He was succeeded by his brother William IV.