The British Empire comprised the
mandates and other
territories ruled or administered by the
United Kingdom and its predecessor states. It originated with the
overseas possessions and
trading posts established by
England between the late 16th and early 18th centuries. At its height, it was the
largest empire in history and, for over a century, was the foremost
global power. By 1913, the British Empire held sway over 412 million people, 23% of the world population at the time,
 and by 1920, it covered 35,500,000 km2 (13,700,000 sq mi),
 24% of the Earth's total land area.
 As a result, its political,
cultural legacy is widespread. At the peak of its power, the phrase "
the empire on which the sun never sets" was often used to describe the British Empire, because its expanse around the globe meant that the sun was always shining on at least one of its territories.
Age of Discovery in the 15th and 16th centuries,
Spain pioneered European exploration of the globe, and in the process established large overseas empires. Envious of the great wealth these empires generated,
France, and the
Netherlands began to establish colonies and trade networks of their own in the Americas and Asia. A series of wars in the 17th and 18th centuries with the Netherlands and France left England and then, following
union between England and Scotland in 1707,
Great Britain, the dominant
colonial power in North America. It then became the dominant power in the
Indian subcontinent after the
East India Company's conquest of
Mughal Bengal at the
Battle of Plassey in 1757.
The independence of the
Thirteen Colonies in North America in 1783 after the
American War of Independence caused Britain to lose some of its oldest and most populous colonies. British attention soon turned towards Asia, Africa, and the Pacific. After the defeat of France in the
Napoleonic Wars (1792–1815), Britain emerged as the principal naval and imperial power of the 19th century.
Unchallenged at sea, British dominance was later described as
Pax Britannica ("British Peace"), a period of relative peace in Europe and the world (1815–1914) during which the British Empire became the global
hegemon and adopted the role of global policeman.
 In the early 19th century, the
Industrial Revolution began to transform Britain; so that by the time of
the Great Exhibition in 1851, the country was described as the "workshop of the world".
 The British Empire expanded to include
most of India, large
parts of Africa and many other territories throughout the world. Alongside the formal control that Britain exerted over its own colonies, its dominance of much of world trade meant that it effectively
controlled the economies of many regions, such as
In Britain, political attitudes favoured free trade and laissez-faire policies and a gradual widening of the voting franchise. During the 19th century, Britain's population increased at a dramatic rate, accompanied by rapid urbanisation, which caused significant social and economic stresses.
 To seek new markets and sources of raw materials, the
Conservative Party under
Benjamin Disraeli launched a period of imperialist expansion in Egypt, South Africa, and elsewhere. Canada, Australia, and New Zealand became self-governing dominions.
By the start of the 20th century,
Germany and the
United States had begun to challenge Britain's economic lead. Subsequent military and economic tensions between Britain and Germany were major causes of the
First World War, during which Britain relied heavily upon its empire. The conflict placed enormous strain on the military, financial and manpower resources of Britain. Although the British Empire achieved its largest territorial extent immediately after World War I, Britain was no longer the world's pre-eminent industrial or military power. In the
Second World War, Britain's colonies in
Southeast Asia were occupied by
Japan. Despite the final victory of Britain and its allies, the damage to British prestige helped to accelerate the decline of the empire. India, Britain's most valuable and populous possession, achieved
independence as part of a larger
decolonisation movement in which Britain granted independence to most territories of the empire. The
transfer of Hong Kong to China in 1997 marked for many the end of the British Empire.
overseas territories remain under British sovereignty.
After independence, many former British colonies joined the
Commonwealth of Nations, a free association of independent states. The United Kingdom is now one of 16 Commonwealth nations, a grouping known informally as the
Commonwealth realms, that share a