Present day Britain was originally inhabited by Celtic tribes in the 6th Century BC. The Roman Empire invaded the island of Britain in 43 BC and established the province of Britannia. When the Romans left, the island was invaded by Germanic tribes like the Angles, the Saxons and the Jute's. The Anglo-Saxon tribes are united in 871 in what became the Kingdom of England, a feudal state. Large parts of the country are conquered by Denmark in the ninth century. By 1016 the Danes ruled the whole country. The Saxons regained power in 1042.
In 1066 England was invaded by the Norman's from Northern France. England became a republic in 1649 after the English Civil War (Known as the Commonwealth of England), but the monarchy was restored in 1660. A second revolution in 1688, lead to a parliamentary system of government or a constitutional monarchy. England and Scotland merged in 1707 into the Kingdom of Great Britain. Years later, Ireland was legally incorporated in the Kingdom under the name United Kingdom of Great Britain and Ireland. By the end of the Napoleonic Wars in 1815, Britain was the foremost European power and its navy ruled the seas. Peace in Europe allows the British to focus their interests on more remote parts of the world and during this period the British Empire reached its zenith. British colonial expansion reached its height largely during the reign of Queen Victoria (1837-1901).
Even as the United Kingdom extends its imperial reach overseas, it continued to develop and broaden its democratic institutions at home. During the nineteenth century parliamentarism developed further. Britain's control over its empire loosened during the inter war period. Ireland, with the exception of six northern counties, gained independence from the United Kingdom in 1921. In 1973, Britain joined the European Community (renamed European Union in 1993.) To read up more on British History click here.