The United Kingdom (UK) comprises the islands of Great Britain and a fragment of north Ireland. Scotland – the northern half of the British Isles – politically merged with England in 1707 to render the United Kingdom of Great Britain.
Wales lies in the western part of England. Wales was annexed by England in the mid-16th century but has retained its cultural identity over the centuries.
Executive power in Great Britain is inseparably intertwined with the tradition of monarchy, which reaches back to the early medieval kings of England, Scotland, and Wales.
The monarchy of the Kingdom of England began with Alfred the Great (849–899) and ended with Queen Anne (1665–1714), who became queen of Great Britain when England merged with Scotland in 1707.
Alfred the Great was King of Wessex at the end of the 9th century. Alfred successfully defended his kingdom against an attempted Viking conquest. Alfred had become the dominant ruler in England by the time he died.
Wessex was an Anglo-Saxon kingdom in south England from 519 until the early 10th century, when England was unified by Athelstan (894–939), who became king. Athelstan centralized government. His legal reforms built upon the work of his grandfather, Alfred the Great.
Athelstan adroitly handled foreign relations, arranging the marriages of several of his sisters to continental rulers. His dominance was acknowledged by Welsh kings.
William I (1028–1087), known as William the Conqueror, was the 1st Norman King of England (1066–1087). A descendant of Viking raiders, William accomplished what Alfred had avoided.