Wales was annexed by the Kingdom of England under the Acts of Union of 15.
A treaty between England and Scotland resulted in 1707 in a unified Kingdom of Great Britain, which merged in 1801 with the Kingdom of Ireland to form the United Kingdom of Great Britain and Ireland.
British influence can be observed in the language, culture, and legal systems of many of its former colonies.
The United Kingdom is a developed country and has the world's fifth-largest economy by nominal GDP and ninth-largest economy by purchasing power parity.
The UK is considered to have a high-income economy and is categorised as very high in the Human Development Index, ranking 14th in the world.
It was the world's first industrialised country and the world's foremost power during the 19th and early 20th centuries.
Lying off the north-western coast of the European mainland, it includes the island of Great Britain (the name of which is also loosely applied to the whole country), the north-eastern part of the island of Ireland, and many smaller islands.
Apart from this land border, the UK is surrounded by the Atlantic Ocean, with the North Sea to its east, the English Channel to its south and the Celtic Sea to its south-southwest, giving it the 12th longest coastline in the world.
The Irish Sea lies between Great Britain and Ireland.
With an area of 242,500 square kilometres (93,600 sq mi), the UK is the 78th-largest sovereign state in the world and the 11th-largest in Europe.
It is also the 21st-most populous country, with an estimated 65.1 million inhabitants.
based in their capitals, Edinburgh, Cardiff, and Belfast, respectively.
The nearby Isle of Man, Bailiwick of Guernsey and Bailiwick of Jersey are not part of the United Kingdom, being Crown dependencies with the British Government responsible for defence and international representation.