The history of the United Kingdom is a complex story of invasions, unions, and global influence.

Ancient & Medieval Foundations

The British Isles were inhabited by Celtic tribes before the Romans invaded in AD 43, establishing the province of Britannia (covering most of modern-day England and Wales) which lasted nearly 400 years. After the Romans left, Anglo-Saxon tribes settled, forming several kingdoms. This was followed by Viking invasions and settlement, particularly in the north and east.

In 1066, the Norman Conquest by William the Conqueror led to a new French-speaking aristocracy and a fundamental shift in culture, language, and architecture. In 1282, King Edward I conquered Wales, which was later formally incorporated into the Kingdom of England through the Laws in Wales Acts 1535 and 1542.

Formation of the United Kingdom

The modern UK was formed through a series of political unions:

• 1603: The Union of the Crowns occurred when James VI of Scotland also became James I of England and Ireland, uniting the three kingdoms under a single monarch.
• 1707: The Acts of Union formally united the kingdoms of England (which included Wales) and Scotland to create the Kingdom of Great Britain.
• 1801: Another Act of Union joined Great Britain with the Kingdom of Ireland, creating the United Kingdom of Great Britain and Ireland.

Empire and Modern Era

From the 1700s, Britain’s power grew, driven by the Industrial Revolution and the expansion of the British Empire, which at its peak covered about a quarter of the world’s landmass.

The 20th century brought immense change. After the First World War, a war of independence in Ireland led to the island’s partition. In 1922, 26 counties became the independent Irish Free State (now the Republic of Ireland), while six counties remained part of the UK. This created the modern-day United Kingdom of Great Britain and Northern Ireland.

After the Second World War, the UK began the process of decolonisation, granting independence to most of its former colonies. In recent decades, power has been devolved from the central UK Parliament in London to national bodies in Scotland, Wales, and Northern Ireland, giving them greater control over their domestic affairs.