George III (1738-1820) of Britain was king during one of the most critical periods in the country's history. He succeeded his grandfather George II in 1760. During the following 60 years, several revolutions modified every aspect of British life. The French Revolution led to a war between Britain and France that threatened Britain's existence. The American Revolution cost Britain the American Colonies that became the United States. The Industrial Revolution created a new society and more than doubled the British population. Britain also acquired new territories in southern Africa, southern Asia, and Australia during the reign of George III. The Act of Union, which became effective in 1801, brought Ireland into the kingdom. The kingdom then became the United Kingdom of Great Britain and Ireland.