The Roman invasion of Britain in 55 BC and most of Britain's consequent incorporation into the Roman Empire stimulated development and brought more active contacts with the rest of Europe. As Rome's strength declined, the nation again was exposed to invasion--including the pivotal incursions of the Angles, Saxons, and Jutes in the fifth and sixth centuries AD--up to the Norman conquest in 1066. Norman rule effectively ensured Britain's safety from further intrusions; certain institutions, which remain characteristic of Britain, could develop. Among these are a political, administrative, cultural, and economic center in London; a separate but accomplished church; a system of common law; typical and distinguished university education; and representative government.

Although often marked by economic and political nationalism, the Commonwealth offers the United Kingdom a voice in matters concerning many developing countries. In addition, the Commonwealth helps preserve many institutions deriving from British experience and models, such as parliamentary democracy, in those countries.