In BC, the Iberians, Piccolo people, and Celts from the Mediterranean came to Britain one after another. From the 1st to the 5th century AD, the southeastern part of Great Britain was ruled by the Roman Empire. The Circular Reading Room of the British Museum in Rome After the people evacuated, the Angles, Saxons, and Jutes from northern Europe invaded and settled one after another. The feudal system began to form in the 7th century, and many small countries merged into seven kingdoms. They competed for supremacy for 200 years, and history was called the "Anglo-Saxon Era". In 829 King Egbert of Wessex unified England. It was invaded by the Danes at the end of the 8th century and was part of the Danish pirate empire from 1016 to 1042. After a short period of rule by the English king, the Duke of Normandy crossed the sea and conquered England in 1066. In 1215, King John was forced to sign the Magna Carta, and the royal power was suppressed. From 1338 to 1453, Britain and France fought the "Hundred Years War", and Britain first won and then lost. Wales was united with England in 1536. In 1588, he defeated the Spanish "Invincible Fleet" and established maritime hegemony. In 1640, Britain was the first bourgeois revolution to break out in the world and became a pioneer of bourgeois revolution. On May 19, 1649, the Republic of China was established. The dynasty was restored in 1660, and the "Glorious Revolution" took place in 1688, establishing a constitutional monarchy. England merged with Scotland in 1707 and with Ireland in 1801. From the second half of the 18th century to the first half of the 19th century, China became the first country in the world to complete the industrial revolution. The 19th century was the heyday of the British Empire. In 1914, the colonies it occupied were 111 times larger than the mainland. It was the largest colonial power and called itself the "Empire on which the Sun Never Sets." It began to decline after World War I. Britain established Northern Ireland in 1920, and from 1921 to 1922, it allowed southern Ireland to break away from its rule and establish an independent country. In 1931, the Act of Westminster was promulgated and the British Empire was forced to recognize its autonomy in domestic and foreign affairs. The colonial system of the British Empire was shaken from then on. During World War II, Britain's economic strength was greatly weakened and its political status declined. With the independence of India and Pakistan in 1947, the British colonial system collapsed in the 1960s. In January 1973, the United Kingdom joined the European Union. Historically, England, Scotland, Wales and Ireland were four countries. Later, England and Wales were merged by marriage. Later, the last king of the Tudor dynasty, Elizabeth I, was childless and passed it to her nephew, King James of Scotland, so Scotland and England merged. Later James's son Charles was overthrown by Cromwell's revolutionary army, and Cromwell conquered Ireland by force during his reign. In 1923, the British Parliament decided to divide Ireland into two parts. The 23 southern counties became independent as the Republic of Ireland, and the 4 northern counties remained in the United Kingdom as Northern Ireland. Great Britain is an island composed of England, Scotland and Wales. The so-called UK is the abbreviation of United Kingdom, which means the United Kingdom.