George IV was 48 when he became Regent in 1811, as a result of the illness of his father, George III. He succeeded to the throne in January 1820.
He had secretly and illegally married a Roman Catholic, Mrs Fitzherber, in 1785. In 1795 he officially married Princess Caroline of Brunswick, but the marriage was a failure and he tried unsuccessfully to divorce her after his accession in 1820 (Caroline died in 1821). Their only child Princess Charlotte died giving birth to a stillborn child, in 1817, aged 21.
An outstanding, if extravagant, collector and builder, George IV acquired many important works of art (now in the Royal Collection), built the Royal Pavilion at Brighton, and transformed Windsor Castle and Buckingham Palace. George's fondness for pageantry helped to develop the ceremonial side of monarchy.
After his father's long illness, George resumed royal visits; he visited Ireland and Hanover in 1821 (it had not been visited by its ruler since the 1750s), and Scotland in 1822, which had not been visited by the monarch since Charles II's Scottish Coronation in 1651.
Beset by debts, George was in a weak position in relation to his Cabinet of ministers. His concern for royal prerogative was sporadic; when the Prime Minister Lord Liverpool fell ill in 1827, George at one stage suggested that ministers should choose Liverpool's successor.
In 1829, George IV was forced by his ministers, much against his will and his interpretation of his coronation oath, to agree to Catholic Emancipation. By reducing religious discrimination, this emancipation enabled the monarchy to play a more national role.
George's profligacy and marriage difficulties meant that he never regained much popularity, and he spent his final years in seclusion at Windsor, dying at the age of 67. His only daughter having died childless, the throne passed to his next brother, William, Duke of Clarence, as William IV.