King George III, King of Great Britain, c 1800.
© Science Museum / Science & Society Picture Library
Engraving of George III (1738-1820) became king in 1760, succeeding his grandfather, George II (1683-1760). George III was determined to govern his kingdom as well as reign, which caused considerable political friction. He was held responsible, together with Lord North, the Prime Minister at the time, for the los of the American colonies. From the 1780s onwards, George suffered bouts of madnes, thought to have been caused by a metabolic disorder known as acute intermittent porphyria, and from 1811 his son the Prince of Wales (later George IV) was made Prince Regent. George III had an active interest in the sciences, and accumulated a substantial collection of scientific instruments, which are today housed at the Science Museum, London.