In the later part of his life, George III suffered from recurrent and, eventually, permanent mental illness. Medical practitioners were baffled by this at the time, although it has since been suggested that he suffered from the blood disease porphyria. 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" which have depended heavily on the prejudices of his biographers and the sources available to them.
George grew into a healthy, but reserved and shy, child. The family moved to Leicester Square, where George and his younger brother Prince Edward, Duke of York and Albany, were educated together by private tutors. Family letters show that he could read and write in both English and German, as well as comment on political events of the time, by the age of eight. He was the first British monarch to study science systematically. Apart from chemistry and physics, his lessons included astronomy, mathematics, French, Latin, history, music, geography, commerce, agriculture and constitutional law, along with sporting and social accomplishments such as dancing, fencing, and riding. His religious education was wholly Anglican.
George's grandfather, King George II, disliked the Prince of Wales and took little interest in his grandchildren. However, in 1751 the Prince of Wales died unexpectedly from a lung injury, and George became heir apparent to the throne. He inherited one of his father's titles and became the Duke of Edinburgh. Now more interested in his grandson, three weeks later the King created George Prince of Wales. (The title is not automatically acquired.)
In the spring of 1756, as George approached his eighteenth birthday, the King offered him a grand establishment at St James's Palace, but George refused the offer, guided by his mother and her confidante, Lord Bute, who would later serve as Prime Minister. George's mother, now the Dowager Princess of Wales, preferred to keep George at home where she could imbue him with her strict moral values.
In late 1810, at the height of his popularity but already virtually blind with cataracts and in pain from rheumatism, George III became dangerously ill. In his view the malady had been triggered by the stress he suffered at the death of his youngest and favourite daughter, Princess Amelia. The Princess's nurse reported that "the scenes of distress and crying every day ... were melancholy beyond description." He accepted the need for the Regency Act 1811 and the Prince of Wales acted as Regent for the remainder of George III's life. By the end of 1811, George III had become permanently insane and lived in seclusion at Windsor Castle until his death.
Perceval was assassinated in 1812 (the only British Prime Minister to have suffered such a fate) and was replaced by Lord Liverpool. Liverpool oversaw British victory in the Napoleonic Wars. The subsequent Congress of Vienna led to significant territorial gains for Hanover, which was upgraded from an electorate to a kingdom.
Meanwhile, George's health deteriorated, and eventually he became completely blind and increasingly deaf. He never knew that he was declared King of Hanover in 1814, or of the death of his wife in 1818. Over Christmas 1819, he spoke nonsense for 58 hours, and for the last few weeks of his life was unable to walk. On 29 January 1820, he died at Windsor Castle. His favourite son, Frederick Duke of York, was with him. His death came six days after that of his fourth son, the Duke of Kent. George III was buried on 16 February in St George's Chapel, Windsor Castle.
George was succeeded by two of his sons George IV and William IV, who both died without surviving legitimate children, leaving the throne to their niece, Victoria, the last monarch of the House of Hanover and the only legitimate child of the Duke of Kent.