George III (1738-1820), king of the United Kingdom of Great Britain and Ireland (1760-1820), who presided over the loss of Britain’s American colonies; he was also elector of the German region of Hannover (1760-1815) and, by decision of the Congress of Vienna, king of Hannover (1815-1820).

George was born in London on June 4, 1738, the oldest son of Frederick Louis, Prince of Wales, and the grandson of King George II. The first of the Hanoverian House to be born and educated as an Englishman, he was primarily interested in his royal prerogatives as king of Great Britain—in contradistinction to his two predecessors, to whom Hannover was the main concern. George’s aim was to rule as well as reign, and he was a skillful and astute intriguer; by 1763 he had managed to regain many of the powers that strong Whig ministries had appropriated during the reigns of the first two Georges. His problem was that he lacked the self-confidence and the mature statesmanship to form and achieve any long-term policy. After the dismissal of several ministers who did not satisfy him, the king found a firm supporter in Frederick North, 2nd earl of Guilford, prime minister from 1770 to 1782. Lord North executed the royal policies that provoked the American Revolution (1775-1783). The unsuccessful conclusion of that protracted conflict forced North to resign, and during the government crisis that followed—when three cabinets came and went in less than two years—the king himself was almost induced to abdicate. He then took a political gamble by placing the government in the hands of the 24-year-old William Pitt, thereby restoring stability for the rest of the century. In line with his belief in royal authority, George favored the wars with France (1793-1815) that grew out of the French Revolution.

In 1809 the king became blind. As early as 1765 he had suffered an apparent dementia, and in 1788 his derangement recurred to such a degree that a regency bill was passed, but the king recovered the following year. It is now thought likely that he had inherited porphyria, a defect of the metabolism that may in time lead to delirium. In 1811 he succumbed hopelessly, and his son, later George IV, acted as regent for the rest of his reign. George III died at Windsor Palace on January 29, 1820.