united into a single Kingdom of Great Britain, with succession under the rules prescribed by the Act of Settlement. In 1714, Queen Anne was succeeded by her second cousin, and Sophia's son, George I, Elector of Hanover, who consolidated his position by defeating Jacobite rebellions in 1715 and 1719. The new monarch was less active in government than many of his British predecessors, but retained control over his German kingdoms, with which Britain was now in personal union. Power shifted towards George's ministers, especially to Sir Robert Walpole, who is often considered the first British prime minister, although the title was not then in use. The next monarch, George II, witnessed the final end of the Jacobite threat in 1746 when the Catholic Stuarts were completely defeated. During the long reign of his grandson, George III, thirteen of Britain's American colonies were lost when they formed the United States of America after the American Revolutionary War, but British influence elsewhere in the world continued to grow. The United Kingdom of Great Britain and Ireland was created by the Acts of Union 1800. From 1811 to 1820, George III suffered a severe bout of what is now believed to be porphyria, an illness rendering him incapable of ruling. His son, the future George IV, ruled in his stead as Prince Regent. During the Regency and his own reign, the power of the monarchy declined, and by the time of his successor, William IV, the monarch was no longer able to effectively interfere with parliamentary power. In 1834, William dismissed the Whig Prime Minister, William Lamb, 2nd Viscount Melbourne, and appointed a Tory, Sir Robert Peel. In the ensuing elections, however, Peel lost. The king had no choice but to recall Lord Melbourne. During William IV's reign, the Reform Act 1832, which reformed parliamentary representation, was passed. Together with others passed later in the century, the Act led to an expansion of the electoral franchise and the rise of the House of Commons as the most important branch of Parliament. The final transition to a constitutional monarchy was made during the long reign of William IV's successor, Victoria. As a woman, Victoria could not rule Hanover, which only permitted succession in the male line, so the personal union of the United Kingdom and Hanover came to an end. The Victorian era was marked by great cultural change, technological progress, and the establishment